add lots of tests and reorganize the code a bit

packages/grafana-data/src/index.ts

@@ -319,7 +319,7 @@ export { type MonacoLanguageRegistryItem, monacoLanguageRegistry } from './monac
 export { createTheme } from './themes/createTheme';
 export { getThemeById, getBuiltInThemes, type ThemeRegistryItem } from './themes/registry';
 export type { NewThemeOptions } from './themes/createTheme';
-export type { ThemeRichColor, GrafanaTheme2, GradientStop } from './themes/types';
+export type { ThemeRichColor, GrafanaTheme2 } from './themes/types';
 export type { ThemeColors } from './themes/createColors';
 export type { ThemeBreakpoints, ThemeBreakpointsKey } from './themes/breakpoints';
 export type { ThemeShadows } from './themes/createShadows';

packages/grafana-data/src/themes/colorManipulator.test.ts

@@ -437,49 +437,4 @@ describe('utils/colorManipulator', () => {
       expect(onBackground('rgba(0,0,255,1)', 'rgba(0,0,0,0.5)').toRgbString()).toBe('rgb(0, 0, 255)');
     });
   });
-
-  describe('colorAtGradientPercent', () => {
-    it('should calculate the color at a given percent in a gradient of two colors', () => {
-      const gradient = [
-        { color: '#ff0000', percent: 0 },
-        { color: '#0000ff', percent: 1 },
-      ];
-      expect(colorAtGradientPercent(gradient, 0).toHexString()).toBe('#ff0000');
-      expect(colorAtGradientPercent(gradient, 0.25).toHexString()).toBe('#bf0040');
-      expect(colorAtGradientPercent(gradient, 0.5).toHexString()).toBe('#800080');
-      expect(colorAtGradientPercent(gradient, 0.75).toHexString()).toBe('#4000bf');
-      expect(colorAtGradientPercent(gradient, 1).toHexString()).toBe('#0000ff');
-    });
-
-    it('should calculate the color at a given percent in a gradient of multiple colors', () => {
-      const gradient = [
-        { color: '#ff0000', percent: 0 },
-        { color: '#00ff00', percent: 0.5 },
-        { color: '#0000ff', percent: 1 },
-      ];
-      expect(colorAtGradientPercent(gradient, 0).toHexString()).toBe('#ff0000');
-      expect(colorAtGradientPercent(gradient, 0.25).toHexString()).toBe('#808000');
-      expect(colorAtGradientPercent(gradient, 0.5).toHexString()).toBe('#00ff00');
-      expect(colorAtGradientPercent(gradient, 0.75).toHexString()).toBe('#008080');
-      expect(colorAtGradientPercent(gradient, 1).toHexString()).toBe('#0000ff');
-    });
-
-    it('should not throw an error when percent is outside 0-1 range', () => {
-      const gradient = [
-        { color: '#ff0000', percent: 0 },
-        { color: '#0000ff', percent: 1 },
-      ];
-      expect(colorAtGradientPercent(gradient, -0.5).toHexString()).toBe('#ff0000');
-      expect(colorAtGradientPercent(gradient, 1.5).toHexString()).toBe('#0000ff');
-    });
-
-    it('should throw an error when less than two stops are provided', () => {
-      expect(() => {
-        colorAtGradientPercent([], 0.5);
-      }).toThrow('colorAtGradientPercent requires at least two color stops');
-      expect(() => {
-        colorAtGradientPercent([{ color: '#ff0000', percent: 0 }], 0.5);
-      }).toThrow('colorAtGradientPercent requires at least two color stops');
-    });
-  });
 });

packages/grafana-data/src/themes/colorManipulator.ts

@@ -4,8 +4,6 @@
 
 import tinycolor from 'tinycolor2';
 
-import { GradientStop } from './types';
-
 /**
  * Returns a number whose value is limited to the given range.
  * @param value The value to be clamped
@@ -394,53 +392,6 @@ export const onBackground = (
   });
 };
 
-/**
- * @alpha
- * Given color stops (each with a color and percentage 0..1) returns the color at a given percentage.
- * Uses tinycolor.mix for interpolation.
- * @params stops - array of color stops (percentages 0..1)
- * @params percent - percentage 0..1
- * @returns color at the given percentage
- */
-export function colorAtGradientPercent(stops: GradientStop[], percent: number): tinycolor.Instance {
-  if (!stops || stops.length < 2) {
-    throw new Error('colorAtGradientPercent requires at least two color stops');
-  }
-
-  // normalize and sort stops by percent
-  const sorted = stops
-    .map((s) => ({ color: s.color, percent: clamp(s.percent, 0, 1) }))
-    .sort((a, b) => a.percent - b.percent);
-
-  // percent outside range
-  if (percent <= sorted[0].percent) {
-    return tinycolor(sorted[0].color);
-  }
-  if (percent >= sorted[sorted.length - 1].percent) {
-    return tinycolor(sorted[sorted.length - 1].color);
-  }
-
-  // find surrounding stops
-  let left = sorted[0];
-  let right = sorted[sorted.length - 1];
-  for (let i = 1; i < sorted.length; i++) {
-    if (percent <= sorted[i].percent) {
-      left = sorted[i - 1];
-      right = sorted[i];
-      break;
-    }
-  }
-
-  const range = right.percent - left.percent;
-  const t = range === 0 ? 0 : (percent - left.percent) / range; // 0..1
-
-  // tinycolor.mix expects amount as percentage of the second color
-  const mixed = tinycolor.mix(left.color, right.color, t * 100);
-
-  // return hex6 if opaque, hex8 if has alpha
-  return mixed;
-}
-
 interface DecomposeColor {
   type: string;
   values: any;
@@ -463,5 +414,4 @@ export const colorManipulator = {
   darken,
   lighten,
   onBackground,
-  colorAtGradientPercent,
 };

packages/grafana-data/src/themes/types.ts

@@ -59,9 +59,3 @@ export interface ThemeRichColor {
 export type DeepPartial<T> = {
   [P in keyof T]?: DeepPartial<T[P]>;
 };
-
-/** @alpha */
-export interface GradientStop {
-  color: string;
-  percent: number;
-}

packages/grafana-ui/src/components/RadialGauge/RadialArcPath.tsx

@@ -1,18 +1,17 @@
 import { useId, useMemo, memo } from 'react';
 
-import { DisplayProcessor, FieldDisplay } from '@grafana/data';
+import { FieldDisplay } from '@grafana/data';
 
 import { useTheme2 } from '../../themes/ThemeContext';
 
-import { RadialGradientMode, RadialShape } from './RadialGauge';
 import { buildGradientColors, getEndpointColors, getGradientCss, getGuideDotColors } from './colors';
-import { drawRadialArcPath, GaugeDimensions, toRad } from './utils';
+import { RadialGradientMode, RadialShape, RadialGaugeDimensions } from './types';
+import { drawRadialArcPath, toRad } from './utils';
 
 export interface RadialArcPathPropsBase {
   arcLengthDeg: number;
   color?: string;
-  dimensions: GaugeDimensions;
-  displayProcessor: DisplayProcessor;
+  dimensions: RadialGaugeDimensions;
   fieldDisplay: FieldDisplay;
   glowFilter?: string;
   gradientMode: RadialGradientMode;
@@ -38,7 +37,6 @@ export const RadialArcPath = memo(
     arcLengthDeg,
     color,
     dimensions,
-    displayProcessor,
     fieldDisplay,
     glowFilter,
     gradientMode,
@@ -54,8 +52,8 @@ export const RadialArcPath = memo(
       if (gradientMode === 'none') {
         return [];
       }
-      return buildGradientColors(gradientMode, theme, displayProcessor, fieldDisplay, fieldDisplay.display.color);
-    }, [gradientMode, fieldDisplay, theme, displayProcessor]);
+      return buildGradientColors(gradientMode, theme, fieldDisplay, fieldDisplay.display.color);
+    }, [gradientMode, fieldDisplay, theme]);
 
     const { guideDotColors, endpointColors } = useMemo(() => {
       if (!showGuideDots || gradientStops.length === 0) {
@@ -67,7 +65,7 @@ export const RadialArcPath = memo(
       return {
         guideDotColors: getGuideDotColors(gradientStops, fieldDisplay.display.percent ?? 0),
         endpointColors:
-          shape === 'circle' ? getEndpointColors(gradientStops, fieldDisplay.display.percent ?? 0) : undefined,
+          shape === 'circle' ? getEndpointColors(gradientStops, fieldDisplay.display.percent ?? 1) : undefined,
       };
     }, [showGuideDots, fieldDisplay, gradientStops, shape]);
 

packages/grafana-ui/src/components/RadialGauge/RadialBar.tsx

@@ -1,16 +1,14 @@
-import { DisplayProcessor, FieldDisplay } from '@grafana/data';
+import { FieldDisplay } from '@grafana/data';
 
 import { useTheme2 } from '../../themes/ThemeContext';
 
 import { RadialArcPath } from './RadialArcPath';
-import { RadialGradientMode, RadialShape } from './RadialGauge';
-import { GaugeDimensions } from './utils';
+import { RadialGradientMode, RadialShape, RadialGaugeDimensions } from './types';
 
 export interface RadialBarProps {
   angle: number;
   angleRange: number;
-  dimensions: GaugeDimensions;
-  displayProcessor: DisplayProcessor;
+  dimensions: RadialGaugeDimensions;
   fieldDisplay: FieldDisplay;
   glowFilter?: string;
   gradientMode: RadialGradientMode;
@@ -22,7 +20,6 @@ export function RadialBar({
   angle,
   angleRange,
   dimensions,
-  displayProcessor,
   fieldDisplay,
   glowFilter,
   gradientMode,
@@ -36,10 +33,9 @@ export function RadialBar({
       {/** Track */}
       <RadialArcPath
         arcLengthDeg={angleRange - angle}
+        fieldDisplay={fieldDisplay}
         color={theme.colors.action.hover}
         dimensions={dimensions}
-        displayProcessor={displayProcessor}
-        fieldDisplay={fieldDisplay}
         gradientMode="none"
         roundedBars={roundedBars}
         shape={shape}
@@ -50,7 +46,6 @@ export function RadialBar({
         arcLengthDeg={angle}
         color={gradientMode === 'none' ? fieldDisplay.display.color : undefined}
         dimensions={dimensions}
-        displayProcessor={displayProcessor}
         fieldDisplay={fieldDisplay}
         glowFilter={glowFilter}
         gradientMode={gradientMode}

packages/grafana-ui/src/components/RadialGauge/RadialBarSegmented.tsx

@@ -1,15 +1,21 @@
-import { DisplayProcessor, FALLBACK_COLOR, FieldDisplay } from '@grafana/data';
+import { memo } from 'react';
+
+import { FALLBACK_COLOR, FieldDisplay } from '@grafana/data';
 
 import { useTheme2 } from '../../themes/ThemeContext';
 
 import { RadialArcPath } from './RadialArcPath';
-import { RadialGradientMode, RadialShape } from './RadialGauge';
-import { GaugeDimensions } from './utils';
+import { RadialGradientMode, RadialShape, RadialGaugeDimensions } from './types';
+import {
+  getAngleBetweenSegments,
+  getFieldConfigMinMax,
+  getFieldDisplayProcessor,
+  getOptimalSegmentCount,
+} from './utils';
 
 export interface RadialBarSegmentedProps {
   fieldDisplay: FieldDisplay;
-  displayProcessor: DisplayProcessor;
-  dimensions: GaugeDimensions;
+  dimensions: RadialGaugeDimensions;
   angleRange: number;
   startAngle: number;
   glowFilter?: string;
@@ -18,75 +24,55 @@ export interface RadialBarSegmentedProps {
   shape: RadialShape;
   gradientMode: RadialGradientMode;
 }
-export function RadialBarSegmented({
-  fieldDisplay,
-  displayProcessor,
-  dimensions,
-  startAngle,
-  angleRange,
-  glowFilter,
-  segmentCount,
-  segmentSpacing,
-  shape,
-  gradientMode,
-}: RadialBarSegmentedProps) {
-  const segments: React.ReactNode[] = [];
-  const theme = useTheme2();
 
-  const segmentCountAdjusted = getOptimalSegmentCount(dimensions, segmentSpacing, segmentCount, angleRange);
-  const min = fieldDisplay.field.min ?? 0;
-  const max = fieldDisplay.field.max ?? 100;
-  const value = fieldDisplay.display.numeric;
-  const angleBetweenSegments = getAngleBetweenSegments(segmentSpacing, segmentCount, angleRange);
-  const segmentArcLengthDeg = angleRange / segmentCountAdjusted - angleBetweenSegments;
+export const RadialBarSegmented = memo(
+  ({
+    fieldDisplay,
+    dimensions,
+    startAngle,
+    angleRange,
+    glowFilter,
+    segmentCount,
+    segmentSpacing,
+    shape,
+    gradientMode,
+  }: RadialBarSegmentedProps) => {
+    const theme = useTheme2();
 
-  for (let i = 0; i < segmentCountAdjusted; i++) {
-    const angleValue = min + ((max - min) / segmentCountAdjusted) * i;
-    const segmentAngle = startAngle + (angleRange / segmentCountAdjusted) * i + 0.01;
-    let segmentColor: string | undefined;
-    if (angleValue >= value) {
-      segmentColor = theme.colors.action.hover;
-    } else if (gradientMode === 'none') {
-      segmentColor = displayProcessor(angleValue).color ?? FALLBACK_COLOR;
+    const segments: React.ReactNode[] = [];
+    const segmentCountAdjusted = getOptimalSegmentCount(dimensions, segmentSpacing, segmentCount, angleRange);
+    const [min, max] = getFieldConfigMinMax(fieldDisplay);
+    const value = fieldDisplay.display.numeric;
+    const angleBetweenSegments = getAngleBetweenSegments(segmentSpacing, segmentCount, angleRange);
+    const segmentArcLengthDeg = angleRange / segmentCountAdjusted - angleBetweenSegments;
+
+    for (let i = 0; i < segmentCountAdjusted; i++) {
+      const angleValue = min + ((max - min) / segmentCountAdjusted) * i;
+      const segmentAngle = startAngle + (angleRange / segmentCountAdjusted) * i + 0.01;
+      let segmentColor: string | undefined;
+      if (angleValue >= value) {
+        segmentColor = theme.colors.action.hover;
+      } else if (gradientMode === 'none') {
+        segmentColor = getFieldDisplayProcessor(fieldDisplay)(angleValue).color ?? FALLBACK_COLOR;
+      }
+
+      segments.push(
+        <RadialArcPath
+          key={i}
+          startAngle={segmentAngle}
+          dimensions={dimensions}
+          fieldDisplay={fieldDisplay}
+          color={segmentColor}
+          shape={shape}
+          glowFilter={glowFilter}
+          arcLengthDeg={segmentArcLengthDeg}
+          gradientMode={gradientMode}
+        />
+      );
     }
 
-    segments.push(
-      <RadialArcPath
-        key={i}
-        startAngle={segmentAngle}
-        dimensions={dimensions}
-        color={segmentColor}
-        shape={shape}
-        glowFilter={glowFilter}
-        arcLengthDeg={segmentArcLengthDeg}
-        gradientMode={gradientMode}
-        fieldDisplay={fieldDisplay}
-        displayProcessor={displayProcessor}
-      />
-    );
+    return <g>{segments}</g>;
   }
+);
 
-  return <g>{segments}</g>;
-}
-
-export function getAngleBetweenSegments(segmentSpacing: number, segmentCount: number, range: number) {
-  // Max spacing is 8 degrees between segments
-  // Changing this constant could be considered a breaking change
-  const maxAngleBetweenSegments = Math.max(range / 1.5 / segmentCount, 2);
-  return segmentSpacing * maxAngleBetweenSegments;
-}
-
-function getOptimalSegmentCount(
-  dimensions: GaugeDimensions,
-  segmentSpacing: number,
-  segmentCount: number,
-  range: number
-) {
-  const angleBetweenSegments = getAngleBetweenSegments(segmentSpacing, segmentCount, range);
-
-  const innerRadius = dimensions.radius - dimensions.barWidth / 2;
-  const circumference = Math.PI * innerRadius * 2 * (range / 360);
-  const maxSegments = Math.floor(circumference / (angleBetweenSegments + 3));
-
-  return Math.min(maxSegments, segmentCount);
-}
+RadialBarSegmented.displayName = 'RadialBarSegmented';

packages/grafana-ui/src/components/RadialGauge/RadialGauge.story.tsx

@@ -13,7 +13,8 @@ import { FieldColorModeId } from '@grafana/schema';
 import { useTheme2 } from '../../themes/ThemeContext';
 import { Stack } from '../Layout/Stack/Stack';
 
-import { RadialGauge, RadialGaugeProps, RadialGradientMode, RadialShape, RadialTextMode } from './RadialGauge';
+import { RadialGauge, RadialGaugeProps } from './RadialGauge';
+import { RadialGradientMode, RadialShape, RadialTextMode } from './types';
 
 interface StoryProps extends RadialGaugeProps {
   value: number;

packages/grafana-ui/src/components/RadialGauge/RadialGauge.tsx

@@ -1,14 +1,7 @@
 import { css, cx } from '@emotion/css';
-import { isNumber } from 'lodash';
 import { useId } from 'react';
 
-import {
-  DisplayValueAlignmentFactors,
-  FieldDisplay,
-  getDisplayProcessor,
-  GrafanaTheme2,
-  TimeRange,
-} from '@grafana/data';
+import { DisplayValueAlignmentFactors, FieldDisplay, GrafanaTheme2, TimeRange } from '@grafana/data';
 import { t } from '@grafana/i18n';
 
 import { useStyles2, useTheme2 } from '../../themes/ThemeContext';
@@ -21,6 +14,7 @@ import { RadialSparkline } from './RadialSparkline';
 import { RadialText } from './RadialText';
 import { ThresholdsBar } from './ThresholdsBar';
 import { GlowGradient, MiddleCircleGlow } from './effects';
+import { RadialGradientMode, RadialShape, RadialTextMode } from './types';
 import { calculateDimensions, getValueAngleForValue } from './utils';
 
 export interface RadialGaugeProps {
@@ -72,10 +66,6 @@ export interface RadialGaugeProps {
   timeRange?: TimeRange;
 }
 
-export type RadialGradientMode = 'none' | 'auto';
-export type RadialTextMode = 'auto' | 'value_and_name' | 'value' | 'name' | 'none';
-export type RadialShape = 'circle' | 'gauge';
-
 /**
  * https://developers.grafana.com/ui/latest/index.html?path=/docs/plugins-radialgauge--docs
  */
@@ -130,7 +120,6 @@ export function RadialGauge(props: RadialGaugeProps) {
       showScaleLabels
     );
 
-    const displayProcessor = getFieldDisplayProcessor(displayValue);
     const glowFilterId = `glow-${gaugeId}`;
 
     if (segmentCount > 1) {
@@ -146,7 +135,6 @@ export function RadialGauge(props: RadialGaugeProps) {
           segmentSpacing={segmentSpacing}
           shape={shape}
           gradientMode={gradient}
-          displayProcessor={displayProcessor}
         />
       );
     } else {
@@ -161,7 +149,6 @@ export function RadialGauge(props: RadialGaugeProps) {
           glowFilter={`url(#${glowFilterId})`}
           shape={shape}
           gradientMode={gradient}
-          displayProcessor={displayProcessor}
           fieldDisplay={displayValue}
         />
       );
@@ -224,7 +211,6 @@ export function RadialGauge(props: RadialGaugeProps) {
               glowFilter={`url(#${glowFilterId})`}
               shape={shape}
               gradientMode={gradient}
-              displayProcessor={displayProcessor}
             />
           );
         }
@@ -270,17 +256,6 @@ export function RadialGauge(props: RadialGaugeProps) {
   );
 }
 
-function getFieldDisplayProcessor(displayValue: FieldDisplay) {
-  if (displayValue.view && isNumber(displayValue.colIndex)) {
-    const dp = displayValue.view.getFieldDisplayProcessor(displayValue.colIndex);
-    if (dp) {
-      return dp;
-    }
-  }
-
-  return getDisplayProcessor();
-}
-
 function getStyles(theme: GrafanaTheme2) {
   return {
     vizWrapper: css({

packages/grafana-ui/src/components/RadialGauge/RadialScaleLabels.tsx

@@ -1,87 +1,84 @@
+import { memo } from 'react';
+
 import { FieldDisplay, GrafanaTheme2, Threshold } from '@grafana/data';
 import { t } from '@grafana/i18n';
 
 import { measureText } from '../../utils/measureText';
 
-import { GaugeDimensions, toCartesian } from './utils';
+import { RadialGaugeDimensions } from './types';
+import { getFieldConfigMinMax, toCartesian } from './utils';
 
 interface RadialScaleLabelsProps {
   fieldDisplay: FieldDisplay;
   theme: GrafanaTheme2;
   thresholds: Threshold[];
-  dimensions: GaugeDimensions;
+  dimensions: RadialGaugeDimensions;
   startAngle: number;
   endAngle: number;
   angleRange: number;
 }
 
-export function RadialScaleLabels({
-  fieldDisplay,
-  thresholds,
-  theme,
-  dimensions,
-  startAngle,
-  endAngle,
-  angleRange,
-}: RadialScaleLabelsProps) {
-  const { centerX, centerY, scaleLabelsFontSize, scaleLabelsRadius } = dimensions;
+const LINE_HEIGHT_FACTOR = 1.2;
 
-  const fieldConfig = fieldDisplay.field;
-  const min = fieldConfig.min ?? 0;
-  const max = fieldConfig.max ?? 100;
+export const RadialScaleLabels = memo(
+  ({ fieldDisplay, thresholds, theme, dimensions, startAngle, endAngle, angleRange }: RadialScaleLabelsProps) => {
+    const { centerX, centerY, scaleLabelsFontSize, scaleLabelsRadius } = dimensions;
+    const [min, max] = getFieldConfigMinMax(fieldDisplay);
 
-  const fontSize = scaleLabelsFontSize;
-  const textLineHeight = scaleLabelsFontSize * 1.2;
-  const radius = scaleLabelsRadius - textLineHeight;
+    const fontSize = scaleLabelsFontSize;
+    const textLineHeight = scaleLabelsFontSize * LINE_HEIGHT_FACTOR;
+    const radius = scaleLabelsRadius - textLineHeight;
 
-  function getTextPosition(text: string, value: number, index: number) {
-    const isLast = index === thresholds.length - 1;
-    const isFirst = index === 0;
+    function getTextPosition(text: string, value: number, index: number) {
+      const isLast = index === thresholds.length - 1;
+      const isFirst = index === 0;
 
-    let valueDeg = ((value - min) / (max - min)) * angleRange;
-    let finalAngle = startAngle + valueDeg;
+      let valueDeg = ((value - min) / (max - min)) * angleRange;
+      let finalAngle = startAngle + valueDeg;
 
-    // Now adjust the final angle based on the label text width and the labels position on the arc
-    let measure = measureText(text, fontSize, theme.typography.fontWeightMedium);
-    let textWidthAngle = (measure.width / (2 * Math.PI * radius)) * angleRange;
+      // Now adjust the final angle based on the label text width and the labels position on the arc
+      let measure = measureText(text, fontSize, theme.typography.fontWeightMedium);
+      let textWidthAngle = (measure.width / (2 * Math.PI * radius)) * angleRange;
 
-    // the centering is different for gauge or circle shapes for some reason
-    finalAngle -= endAngle < 180 ? textWidthAngle : textWidthAngle / 2;
+      // the centering is different for gauge or circle shapes for some reason
+      finalAngle -= endAngle < 180 ? textWidthAngle : textWidthAngle / 2;
 
-    // For circle gauges we need to shift the first label more
-    if (isFirst) {
-      finalAngle += textWidthAngle;
+      // For circle gauges we need to shift the first label more
+      if (isFirst) {
+        finalAngle += textWidthAngle;
+      }
+
+      // For circle gauges we need to shift the last label more
+      if (isLast && endAngle === 360) {
+        finalAngle -= textWidthAngle;
+      }
+
+      const position = toCartesian(centerX, centerY, radius, finalAngle);
+
+      return { ...position, transform: `rotate(${finalAngle}, ${position.x}, ${position.y})` };
     }
 
-    // For circle gauges we need to shift the last label more
-    if (isLast && endAngle === 360) {
-      finalAngle -= textWidthAngle;
-    }
-
-    const position = toCartesian(centerX, centerY, radius, finalAngle);
-
-    return { ...position, transform: `rotate(${finalAngle}, ${position.x}, ${position.y})` };
+    return (
+      <g>
+        {thresholds.map((threshold, index) => {
+          const labelPos = getTextPosition(String(threshold.value), threshold.value, index);
+          return (
+            <text
+              key={index}
+              x={labelPos.x}
+              y={labelPos.y}
+              fontSize={fontSize}
+              fill={theme.colors.text.primary}
+              transform={labelPos.transform}
+              aria-label={t(`gauge.threshold`, 'Threshold {{value}}', { value: threshold.value })}
+            >
+              {threshold.value}
+            </text>
+          );
+        })}
+      </g>
+    );
   }
+);
 
-  return (
-    <g>
-      {thresholds.map((threshold, index) => {
-        const labelPos = getTextPosition(String(threshold.value), threshold.value, index);
-
-        return (
-          <text
-            key={index}
-            x={labelPos.x}
-            y={labelPos.y}
-            fontSize={fontSize}
-            fill={theme.colors.text.primary}
-            transform={labelPos.transform}
-            aria-label={t(`gauge.threshold`, 'Threshold {{value}}', { value: threshold.value })}
-          >
-            {threshold.value}
-          </text>
-        );
-      })}
-    </g>
-  );
-}
+RadialScaleLabels.displayName = 'RadialScaleLabels';

packages/grafana-ui/src/components/RadialGauge/RadialSparkline.tsx

@@ -3,17 +3,25 @@ import { GraphFieldConfig, GraphGradientMode, LineInterpolation } from '@grafana
 
 import { Sparkline } from '../Sparkline/Sparkline';
 
-import { RadialShape, RadialTextMode } from './RadialGauge';
-import { GaugeDimensions } from './utils';
+import { RadialShape, RadialTextMode, RadialGaugeDimensions } from './types';
 
 interface RadialSparklineProps {
   sparkline: FieldDisplay['sparkline'];
-  dimensions: GaugeDimensions;
+  dimensions: RadialGaugeDimensions;
   theme: GrafanaTheme2;
   color?: string;
   shape?: RadialShape;
   textMode: Exclude<RadialTextMode, 'auto'>;
 }
+
+const SPARKLINE_HEIGHT_DIVISOR = 4;
+const SPARKLINE_HEIGHT_DIVISOR_NAME_AND_VALUE = 4;
+const SPARKLINE_WIDTH_FACTOR_ARC = 1.4;
+const SPARKLINE_WIDTH_FACTOR_CIRCLE = 1.6;
+const SPARKLINE_TOP_OFFSET_DIVISOR_CIRCLE = 4;
+const SPARKLINE_TOP_OFFSET_DIVISOR_CIRCLE_NAME_AND_VALUE = 3.3;
+const SPARKLINE_SPACING = 8;
+
 export function RadialSparkline({ sparkline, dimensions, theme, color, shape, textMode }: RadialSparklineProps) {
   const { radius, barWidth } = dimensions;
 
@@ -22,12 +30,12 @@ export function RadialSparkline({ sparkline, dimensions, theme, color, shape, te
   }
 
   const showNameAndValue = textMode === 'value_and_name';
-  const height = radius / (showNameAndValue ? 4 : 3);
-  const width = radius * (shape === 'gauge' ? 1.6 : 1.4) - barWidth;
+  const height = radius / (showNameAndValue ? SPARKLINE_HEIGHT_DIVISOR_NAME_AND_VALUE : SPARKLINE_HEIGHT_DIVISOR);
+  const width = radius * (shape === 'gauge' ? SPARKLINE_WIDTH_FACTOR_ARC : SPARKLINE_WIDTH_FACTOR_CIRCLE) - barWidth;
   const topPos =
     shape === 'gauge'
-      ? `${dimensions.gaugeBottomY - height}px`
-      : `calc(50% + ${radius / (showNameAndValue ? 3.3 : 4)}px)`;
+      ? dimensions.gaugeBottomY - height - SPARKLINE_SPACING
+      : `calc(50% + ${radius / (showNameAndValue ? SPARKLINE_TOP_OFFSET_DIVISOR_CIRCLE_NAME_AND_VALUE : SPARKLINE_TOP_OFFSET_DIVISOR_CIRCLE)}px)`;
 
   const config: FieldConfig<GraphFieldConfig> = {
     color: {

packages/grafana-ui/src/components/RadialGauge/RadialText.tsx

@@ -1,4 +1,5 @@
 import { css } from '@emotion/css';
+import { memo } from 'react';
 
 import {
   DisplayValue,
@@ -11,13 +12,12 @@ import {
 import { useStyles2 } from '../../themes/ThemeContext';
 import { calculateFontSize } from '../../utils/measureText';
 
-import { RadialShape, RadialTextMode } from './RadialGauge';
-import { GaugeDimensions } from './utils';
+import { RadialShape, RadialTextMode, RadialGaugeDimensions } from './types';
 
 interface RadialTextProps {
   displayValue: DisplayValue;
   theme: GrafanaTheme2;
-  dimensions: GaugeDimensions;
+  dimensions: RadialGaugeDimensions;
   textMode: Exclude<RadialTextMode, 'auto'>;
   shape: RadialShape;
   sparkline?: FieldSparkline;
@@ -26,123 +26,131 @@ interface RadialTextProps {
   nameManualFontSize?: number;
 }
 
-export function RadialText({
-  displayValue,
-  theme,
-  dimensions,
-  textMode,
-  shape,
-  sparkline,
-  alignmentFactors,
-  valueManualFontSize,
-  nameManualFontSize,
-}: RadialTextProps) {
-  const styles = useStyles2(getStyles);
-  const { centerX, centerY, radius, barWidth } = dimensions;
+const LINE_HEIGHT_FACTOR = 1.21;
+const VALUE_WIDTH_TO_RADIUS_FACTOR = 0.82;
+const NAME_TO_HEIGHT_FACTOR = 0.45;
+const LARGE_RADIUS_SCALING_DECAY = 0.86;
+const MAX_TEXT_WIDTH_DIVISOR = 7;
+const MAX_NAME_HEIGHT_DIVISOR = 4;
+const VALUE_SPACE_PERCENTAGE = 0.7;
+const SPARKLINE_SPACING = 8;
+const MIN_UNIT_FONT_SIZE = 5;
 
-  if (textMode === 'none') {
-    return null;
-  }
+export const RadialText = memo(
+  ({
+    displayValue,
+    theme,
+    dimensions,
+    textMode,
+    shape,
+    sparkline,
+    alignmentFactors,
+    valueManualFontSize,
+    nameManualFontSize,
+  }: RadialTextProps) => {
+    const styles = useStyles2(getStyles);
+    const { centerX, centerY, radius, barWidth } = dimensions;
 
-  const nameToAlignTo = (alignmentFactors ? alignmentFactors.title : displayValue.title) ?? '';
-  const valueToAlignTo = formattedValueToString(alignmentFactors ? alignmentFactors : displayValue);
+    if (textMode === 'none') {
+      return null;
+    }
 
-  const showValue = textMode === 'value' || textMode === 'value_and_name';
-  const showName = textMode === 'name' || textMode === 'value_and_name';
-  const maxTextWidth = radius * 2 - barWidth - radius / 7;
+    const nameToAlignTo = (alignmentFactors ? alignmentFactors.title : displayValue.title) ?? '';
+    const valueToAlignTo = formattedValueToString(alignmentFactors ? alignmentFactors : displayValue);
 
-  // Not sure where this comes from but svg text is not using body line-height
-  const lineHeight = 1.21;
-  const valueWidthToRadiusFactor = 0.82;
-  const nameToHeightFactor = 0.45;
-  const largeRadiusScalingDecay = 0.86;
+    const showValue = textMode === 'value' || textMode === 'value_and_name';
+    const showName = textMode === 'name' || textMode === 'value_and_name';
+    const maxTextWidth = radius * 2 - barWidth - radius / MAX_TEXT_WIDTH_DIVISOR;
 
-  // This pow 0.92 factor is to create a decay so the font size does not become rediculously large for very large panels
-  let maxValueHeight = valueWidthToRadiusFactor * Math.pow(radius, largeRadiusScalingDecay);
-  let maxNameHeight = radius / 4;
+    // This pow 0.92 factor is to create a decay so the font size does not become rediculously large for very large panels
+    let maxValueHeight = VALUE_WIDTH_TO_RADIUS_FACTOR * Math.pow(radius, LARGE_RADIUS_SCALING_DECAY);
+    let maxNameHeight = radius / MAX_NAME_HEIGHT_DIVISOR;
 
-  if (showValue && showName) {
-    maxValueHeight = valueWidthToRadiusFactor * Math.pow(radius, largeRadiusScalingDecay);
-    maxNameHeight = nameToHeightFactor * Math.pow(radius, largeRadiusScalingDecay);
-  }
+    if (showValue && showName) {
+      maxValueHeight = VALUE_WIDTH_TO_RADIUS_FACTOR * Math.pow(radius, LARGE_RADIUS_SCALING_DECAY);
+      maxNameHeight = NAME_TO_HEIGHT_FACTOR * Math.pow(radius, LARGE_RADIUS_SCALING_DECAY);
+    }
 
-  const valueFontSize =
-    valueManualFontSize ??
-    calculateFontSize(
-      valueToAlignTo,
-      maxTextWidth,
-      maxValueHeight,
-      lineHeight,
-      undefined,
-      theme.typography.body.fontWeight
+    const valueFontSize =
+      valueManualFontSize ??
+      calculateFontSize(
+        valueToAlignTo,
+        maxTextWidth,
+        maxValueHeight,
+        LINE_HEIGHT_FACTOR,
+        undefined,
+        theme.typography.body.fontWeight
+      );
+
+    const nameFontSize =
+      nameManualFontSize ??
+      calculateFontSize(
+        nameToAlignTo,
+        maxTextWidth,
+        maxNameHeight,
+        LINE_HEIGHT_FACTOR,
+        undefined,
+        theme.typography.body.fontWeight
+      );
+
+    const unitFontSize = Math.max(valueFontSize * VALUE_SPACE_PERCENTAGE, MIN_UNIT_FONT_SIZE);
+    const valueHeight = valueFontSize * LINE_HEIGHT_FACTOR;
+    const nameHeight = nameFontSize * LINE_HEIGHT_FACTOR;
+
+    const valueY = showName ? centerY - nameHeight * (1 - VALUE_SPACE_PERCENTAGE) : centerY;
+    const nameY = showValue ? valueY + valueHeight * VALUE_SPACE_PERCENTAGE : centerY;
+    const nameColor = showValue ? theme.colors.text.secondary : theme.colors.text.primary;
+    const suffixShift = (valueFontSize - unitFontSize * LINE_HEIGHT_FACTOR) / 2;
+
+    // adjust the text up on gauges and when sparklines are present
+    let yOffset = 0;
+    if (shape === 'gauge') {
+      // we render from the center of the gauge, so move up by half of half of the total height
+      yOffset -= (valueHeight + nameHeight) / 4;
+    }
+    if (sparkline) {
+      yOffset -= SPARKLINE_SPACING;
+    }
+
+    return (
+      <g transform={`translate(0, ${yOffset})`}>
+        {showValue && (
+          <text
+            x={centerX}
+            y={valueY}
+            fontSize={valueFontSize}
+            fill={theme.colors.text.primary}
+            className={styles.text}
+            textAnchor="middle"
+            dominantBaseline="middle"
+          >
+            <tspan fontSize={unitFontSize}>{displayValue.prefix ?? ''}</tspan>
+            <tspan>{displayValue.text}</tspan>
+            <tspan className={styles.text} fontSize={unitFontSize} dy={suffixShift}>
+              {displayValue.suffix ?? ''}
+            </tspan>
+          </text>
+        )}
+        {showName && (
+          <text
+            fontSize={nameFontSize}
+            x={centerX}
+            y={nameY}
+            textAnchor="middle"
+            dominantBaseline="middle"
+            fill={nameColor}
+          >
+            {displayValue.title}
+          </text>
+        )}
+      </g>
     );
-
-  const nameFontSize =
-    nameManualFontSize ??
-    calculateFontSize(
-      nameToAlignTo,
-      maxTextWidth,
-      maxNameHeight,
-      lineHeight,
-      undefined,
-      theme.typography.body.fontWeight
-    );
-
-  const unitFontSize = Math.max(valueFontSize * 0.7, 5);
-  const valueHeight = valueFontSize * lineHeight;
-  const nameHeight = nameFontSize * lineHeight;
-
-  const valueY = showName ? centerY - nameHeight * 0.3 : centerY;
-  const nameY = showValue ? valueY + valueHeight * 0.7 : centerY;
-  const nameColor = showValue ? theme.colors.text.secondary : theme.colors.text.primary;
-  const suffixShift = (valueFontSize - unitFontSize * 1.2) / 2;
-
-  // adjust the text up on gauges and when sparklines are present
-  let yOffset = 0;
-  if (shape === 'gauge') {
-    // we render from the center of the gauge, so move up by half of half of the total height
-    yOffset -= (valueHeight + nameHeight) / 4;
-  }
-  if (sparkline) {
-    yOffset -= 8;
   }
+);
 
-  return (
-    <g transform={`translate(0, ${yOffset})`}>
-      {showValue && (
-        <text
-          x={centerX}
-          y={valueY}
-          fontSize={valueFontSize}
-          fill={theme.colors.text.primary}
-          className={styles.text}
-          textAnchor="middle"
-          dominantBaseline="middle"
-        >
-          <tspan fontSize={unitFontSize}>{displayValue.prefix ?? ''}</tspan>
-          <tspan>{displayValue.text}</tspan>
-          <tspan className={styles.text} fontSize={unitFontSize} dy={suffixShift}>
-            {displayValue.suffix ?? ''}
-          </tspan>
-        </text>
-      )}
-      {showName && (
-        <text
-          fontSize={nameFontSize}
-          x={centerX}
-          y={nameY}
-          textAnchor="middle"
-          dominantBaseline="middle"
-          fill={nameColor}
-        >
-          {displayValue.title}
-        </text>
-      )}
-    </g>
-  );
-}
+RadialText.displayName = 'RadialText';
 
-const getStyles = (theme: GrafanaTheme2) => ({
+const getStyles = (_theme: GrafanaTheme2) => ({
   text: css({
     verticalAlign: 'bottom',
   }),

packages/grafana-ui/src/components/RadialGauge/ThresholdsBar.tsx

@@ -1,11 +1,11 @@
-import { DisplayProcessor, FieldDisplay, Threshold } from '@grafana/data';
+import { FieldDisplay, Threshold } from '@grafana/data';
 
 import { RadialArcPath } from './RadialArcPath';
-import { RadialGradientMode, RadialShape } from './RadialGauge';
-import { GaugeDimensions } from './utils';
+import { RadialGaugeDimensions, RadialGradientMode, RadialShape } from './types';
+import { getFieldConfigMinMax } from './utils';
 
-export interface Props {
-  dimensions: GaugeDimensions;
+interface ThresholdsBarProps {
+  dimensions: RadialGaugeDimensions;
   angleRange: number;
   startAngle: number;
   endAngle: number;
@@ -15,8 +15,8 @@ export interface Props {
   glowFilter?: string;
   thresholds: Threshold[];
   gradientMode: RadialGradientMode;
-  displayProcessor: DisplayProcessor;
 }
+
 export function ThresholdsBar({
   dimensions,
   fieldDisplay,
@@ -27,18 +27,15 @@ export function ThresholdsBar({
   thresholds,
   shape,
   gradientMode,
-  displayProcessor,
-}: Props) {
-  const fieldConfig = fieldDisplay.field;
-  const min = fieldConfig.min ?? 0;
-  const max = fieldConfig.max ?? 100;
-
+}: ThresholdsBarProps) {
   const thresholdDimensions = {
     ...dimensions,
     barWidth: dimensions.thresholdsBarWidth,
     radius: dimensions.thresholdsBarRadius,
   };
 
+  const [min, max] = getFieldConfigMinMax(fieldDisplay);
+
   let currentStart = startAngle;
   let paths: React.ReactNode[] = [];
 
@@ -52,21 +49,21 @@ export function ThresholdsBar({
       valueDeg = 0;
     }
 
-    let lengthDeg = valueDeg - currentStart + startAngle;
+    const lengthDeg = valueDeg - currentStart + startAngle;
+    const color = gradientMode === 'none' ? threshold.color : undefined;
 
     paths.push(
       <RadialArcPath
         key={i}
-        startAngle={currentStart}
         arcLengthDeg={lengthDeg}
-        color={gradientMode === 'none' ? threshold.color : undefined}
-        shape={shape}
+        color={color}
         dimensions={thresholdDimensions}
-        roundedBars={roundedBars}
+        fieldDisplay={fieldDisplay}
         glowFilter={glowFilter}
         gradientMode={gradientMode}
-        displayProcessor={displayProcessor}
-        fieldDisplay={fieldDisplay}
+        roundedBars={roundedBars}
+        shape={shape}
+        startAngle={currentStart}
       />
     );
 

packages/grafana-ui/src/components/RadialGauge/__snapshots__/utils.test.ts.snap

@@ -0,0 +1,17 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for center x and y 1`] = `"M 150 110 A 90 90 0 1 1 149.98429203681178 110.00000137077838 A 10 10 0 0 1 149.98778269529805 130.00000106616096 A 70 70 0 1 0 150 130 A 10 10 0 0 1 150 110 Z"`;
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for half arc 1`] = `"M 100 10 A 90 90 0 0 1 100 190 L 100 170 A 70 70 0 0 0 100 30 L 100 10 Z"`;
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for narrow bar width 1`] = `"M 100 17.5 A 82.5 82.5 0 0 1 100 182.5 L 100 177.5 A 77.5 77.5 0 0 0 100 22.5 L 100 17.5 Z"`;
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for narrow radius 1`] = `"M 100 40 A 60 60 0 0 1 100 160 L 100 140 A 40 40 0 0 0 100 60 L 100 40 Z"`;
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for quarter arc 1`] = `"M 100 10 A 90 90 0 0 1 190 100 L 170 100 A 70 70 0 0 0 100 30 L 100 10 Z"`;
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for rounded bars 1`] = `"M 100 10 A 90 90 0 1 1 10 100.00000000000001 A 10 10 0 0 1 30 100.00000000000001 A 70 70 0 1 0 100 30 A 10 10 0 0 1 100 10 Z"`;
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for three quarter arc 1`] = `"M 100 10 A 90 90 0 1 1 10 100.00000000000001 L 30 100.00000000000001 A 70 70 0 1 0 100 30 L 100 10 Z"`;
+
+exports[`RadialGauge utils drawRadialArcPath should draw correct path for wide bar width 1`] = `"M 100 -5 A 105 105 0 0 1 100 205 L 100 155 A 55 55 0 0 0 100 45 L 100 -5 Z"`;

packages/grafana-ui/src/components/RadialGauge/colors.test.ts

@@ -0,0 +1,286 @@
+import { defaultsDeep } from 'lodash';
+
+import { createTheme, FALLBACK_COLOR, Field, FieldDisplay, FieldType, ThresholdsMode } from '@grafana/data';
+import { FieldColorModeId } from '@grafana/schema';
+
+import {
+  buildGradientColors,
+  colorAtGradientPercent,
+  getEndpointColors,
+  getGradientCss,
+  getGuideDotColors,
+} from './colors';
+
+export type DeepPartial<T> = {
+  [P in keyof T]?: DeepPartial<T[P]>;
+};
+
+describe('RadialGauge color utils', () => {
+  describe('buildGradientColors', () => {
+    const createField = (colorMode: FieldColorModeId): Field =>
+      ({
+        type: FieldType.number,
+        name: 'Test Field',
+        config: {
+          color: {
+            mode: colorMode,
+          },
+          thresholds: {
+            mode: ThresholdsMode.Absolute,
+            steps: [
+              { value: -Infinity, color: 'green' },
+              { value: 50, color: 'yellow' },
+              { value: 80, color: 'red' },
+            ],
+          },
+        },
+        values: [70, 40, 30, 90, 55],
+      }) satisfies Field;
+
+    const buildFieldDisplay = (field: Field, part = {}): FieldDisplay =>
+      defaultsDeep(part, {
+        field: field.config,
+        colIndex: 0,
+        view: {
+          getFieldDisplayProcessor: jest.fn(() => jest.fn(() => ({ color: undefined }))),
+        },
+        display: {
+          numeric: 75,
+        },
+      });
+
+    it('should return the baseColor if gradientMode is none', () => {
+      expect(
+        buildGradientColors('none', createTheme(), buildFieldDisplay(createField(FieldColorModeId.Fixed)), '#FF0000')
+      ).toEqual([
+        { color: '#FF0000', percent: 0 },
+        { color: '#FF0000', percent: 1 },
+      ]);
+    });
+
+    it('uses the fallback color if no baseColor is set', () => {
+      expect(
+        buildGradientColors('none', createTheme(), buildFieldDisplay(createField(FieldColorModeId.Fixed)))
+      ).toEqual([
+        { color: FALLBACK_COLOR, percent: 0 },
+        { color: FALLBACK_COLOR, percent: 1 },
+      ]);
+    });
+
+    it('should map threshold colors correctly (with baseColor if displayProcessor does not return colors)', () => {
+      expect(
+        buildGradientColors(
+          'auto',
+          createTheme(),
+          buildFieldDisplay(createField(FieldColorModeId.Thresholds), {
+            view: { getFieldDisplayProcessor: jest.fn(() => jest.fn(() => ({ color: '#444444' }))) },
+          })
+        )
+      ).toEqual([
+        { color: '#444444', percent: 0 },
+        { color: '#FADE2A', percent: 0.5 },
+        { color: '#F2495C', percent: 0.8 },
+        { color: '#444444', percent: 1 },
+      ]);
+    });
+
+    it('should map threshold colors correctly (with baseColor if displayProcessor does not return colors)', () => {
+      expect(
+        buildGradientColors(
+          'auto',
+          createTheme(),
+          buildFieldDisplay(createField(FieldColorModeId.Thresholds)),
+          '#FF0000'
+        )
+      ).toEqual([
+        { color: '#FF0000', percent: 0 },
+        { color: '#FADE2A', percent: 0.5 },
+        { color: '#F2495C', percent: 0.8 },
+        { color: '#FF0000', percent: 1 },
+      ]);
+    });
+
+    it('should return gradient colors for continuous color modes', () => {
+      expect(
+        buildGradientColors(
+          'auto',
+          createTheme(),
+          buildFieldDisplay(createField(FieldColorModeId.ContinuousCividis)),
+          '#00FF00'
+        )
+      ).toEqual([
+        {
+          color: 'rgb(0, 32, 81)',
+          percent: 0,
+        },
+        {
+          color: 'rgb(17, 54, 108)',
+          percent: 0.125,
+        },
+        {
+          color: 'rgb(60, 77, 110)',
+          percent: 0.25,
+        },
+        {
+          color: 'rgb(98, 100, 111)',
+          percent: 0.375,
+        },
+        {
+          color: 'rgb(127, 124, 117)',
+          percent: 0.5,
+        },
+        {
+          color: 'rgb(154, 148, 120)',
+          percent: 0.625,
+        },
+        {
+          color: 'rgb(187, 175, 113)',
+          percent: 0.75,
+        },
+        {
+          color: 'rgb(226, 203, 92)',
+          percent: 0.875,
+        },
+        {
+          color: 'rgb(253, 234, 69)',
+          percent: 1,
+        },
+      ]);
+    });
+
+    it('should return gradient colors for by-value color modes', () => {
+      expect(
+        buildGradientColors('auto', createTheme(), buildFieldDisplay(createField(FieldColorModeId.ContinuousBlues)))
+      ).toEqual([
+        { color: '#181b1f', percent: 0 },
+        { color: '#1F60C4', percent: 1 },
+      ]);
+    });
+
+    it('should return gradient colors for fixed color mode', () => {
+      expect(
+        buildGradientColors('auto', createTheme(), buildFieldDisplay(createField(FieldColorModeId.Fixed)), '#442299')
+      ).toEqual([
+        { color: '#14175a', percent: 0 },
+        { color: '#a146da', percent: 1 },
+      ]);
+    });
+  });
+
+  describe('colorAtGradientPercent', () => {
+    it('should calculate the color at a given percent in a gradient of two colors', () => {
+      const gradient = [
+        { color: '#ff0000', percent: 0 },
+        { color: '#0000ff', percent: 1 },
+      ];
+      expect(colorAtGradientPercent(gradient, 0).toHexString()).toBe('#ff0000');
+      expect(colorAtGradientPercent(gradient, 0.25).toHexString()).toBe('#bf0040');
+      expect(colorAtGradientPercent(gradient, 0.5).toHexString()).toBe('#800080');
+      expect(colorAtGradientPercent(gradient, 0.75).toHexString()).toBe('#4000bf');
+      expect(colorAtGradientPercent(gradient, 1).toHexString()).toBe('#0000ff');
+    });
+
+    it('should calculate the color at a given percent in a gradient of multiple colors', () => {
+      const gradient = [
+        { color: '#ff0000', percent: 0 },
+        { color: '#00ff00', percent: 0.5 },
+        { color: '#0000ff', percent: 1 },
+      ];
+      expect(colorAtGradientPercent(gradient, 0).toHexString()).toBe('#ff0000');
+      expect(colorAtGradientPercent(gradient, 0.25).toHexString()).toBe('#808000');
+      expect(colorAtGradientPercent(gradient, 0.5).toHexString()).toBe('#00ff00');
+      expect(colorAtGradientPercent(gradient, 0.75).toHexString()).toBe('#008080');
+      expect(colorAtGradientPercent(gradient, 1).toHexString()).toBe('#0000ff');
+    });
+
+    it('should not throw an error when percent is outside 0-1 range', () => {
+      const gradient = [
+        { color: '#ff0000', percent: 0 },
+        { color: '#0000ff', percent: 1 },
+      ];
+      expect(colorAtGradientPercent(gradient, -0.5).toHexString()).toBe('#ff0000');
+      expect(colorAtGradientPercent(gradient, 1.5).toHexString()).toBe('#0000ff');
+    });
+
+    it('should throw an error when less than two stops are provided', () => {
+      expect(() => {
+        colorAtGradientPercent([], 0.5);
+      }).toThrow('colorAtGradientPercent requires at least two color stops');
+      expect(() => {
+        colorAtGradientPercent([{ color: '#ff0000', percent: 0 }], 0.5);
+      }).toThrow('colorAtGradientPercent requires at least two color stops');
+    });
+  });
+
+  describe('getEndpointColors', () => {
+    it('should return the first and last colors in the gradient', () => {
+      const gradient = [
+        { color: '#ff0000', percent: 0 },
+        { color: '#00ff00', percent: 0.5 },
+        { color: '#0000ff', percent: 1 },
+      ];
+      const [startColor, endColor] = getEndpointColors(gradient);
+      expect(startColor).toBe('#ff0000');
+      expect(endColor).toBe('#0000ff');
+    });
+
+    it('should return the correct end color based on percent', () => {
+      const gradient = [
+        { color: '#ff0000', percent: 0 },
+        { color: '#00ff00', percent: 0.5 },
+        { color: '#0000ff', percent: 1 },
+      ];
+      const [startColor, endColor] = getEndpointColors(gradient, 0.25);
+      expect(startColor).toBe('#ff0000');
+      expect(endColor).toBe('#808000');
+    });
+
+    it('should handle gradients with only one colors', () => {
+      const gradient = [{ color: '#ff0000', percent: 0 }];
+      const [startColor, endColor] = getEndpointColors(gradient);
+      expect(startColor).toBe('#ff0000');
+      expect(endColor).toBe('#ff0000');
+    });
+
+    it('should throw an error when no colors are provided', () => {
+      expect(() => {
+        getEndpointColors([]);
+      }).toThrow('getEndpointColors requires at least one color stop');
+    });
+  });
+
+  describe('getGradientCss', () => {
+    it('should return conic-gradient CSS for circle shape', () => {
+      const gradient = [
+        { color: '#ff0000', percent: 0 },
+        { color: '#00ff00', percent: 0.5 },
+        { color: '#0000ff', percent: 1 },
+      ];
+      const css = getGradientCss(gradient, 'circle');
+      expect(css).toBe('conic-gradient(from 0deg, #ff0000 0.00%, #00ff00 50.00%, #0000ff 100.00%)');
+    });
+
+    it('should return linear-gradient CSS for arc shape', () => {
+      const gradient = [
+        { color: '#ff0000', percent: 0 },
+        { color: '#00ff00', percent: 0.5 },
+        { color: '#0000ff', percent: 1 },
+      ];
+      const css = getGradientCss(gradient, 'gauge');
+      expect(css).toBe('linear-gradient(90deg, #ff0000 0.00%, #00ff00 50.00%, #0000ff 100.00%)');
+    });
+  });
+
+  describe('getGuideDotColors', () => {
+    it('should return contrasting guide dot colors based on the gradient endpoints and percent', () => {
+      const gradient = [
+        { color: '#000000', percent: 0 },
+        { color: '#ffffff', percent: 0.5 },
+        { color: '#ffffff', percent: 1 },
+      ];
+      const [startDotColor, endDotColor] = getGuideDotColors(gradient, 0.35);
+      expect(startDotColor).toBe('#fbfbfb');
+      expect(endDotColor).toBe('#111217');
+    });
+  });
+});

packages/grafana-ui/src/components/RadialGauge/colors.ts

@@ -1,25 +1,16 @@
 import tinycolor from 'tinycolor2';
 
-import {
-  colorManipulator,
-  DisplayProcessor,
-  FALLBACK_COLOR,
-  FieldDisplay,
-  getFieldColorMode,
-  GradientStop,
-  GrafanaTheme2,
-} from '@grafana/data';
+import { colorManipulator, FALLBACK_COLOR, FieldDisplay, getFieldColorMode, GrafanaTheme2 } from '@grafana/data';
 import { FieldColorModeId } from '@grafana/schema';
 
-import { RadialGradientMode, RadialShape } from './RadialGauge';
+import { GradientStop, RadialGradientMode, RadialShape } from './types';
+import { getFieldConfigMinMax, getFieldDisplayProcessor } from './utils';
 
 export function buildGradientColors(
   gradientMode: RadialGradientMode,
   theme: GrafanaTheme2,
-  displayProcessor: DisplayProcessor,
   fieldDisplay: FieldDisplay,
-  baseColor = FALLBACK_COLOR,
-  forSegment?: boolean
+  baseColor = FALLBACK_COLOR
 ): GradientStop[] {
   if (gradientMode === 'none') {
     return [
@@ -30,13 +21,14 @@ export function buildGradientColors(
 
   const colorMode = getFieldColorMode(fieldDisplay.field.color?.mode);
 
+  // thresholds get special handling
   if (colorMode.id === FieldColorModeId.Thresholds) {
+    const displayProcessor = getFieldDisplayProcessor(fieldDisplay);
+    const [min, max] = getFieldConfigMinMax(fieldDisplay);
     const thresholds = fieldDisplay.field.thresholds?.steps ?? [];
-    const min = fieldDisplay.field.min ?? 0;
-    const max = fieldDisplay.field.max ?? 100;
 
     const result: Array<{ color: string; percent: number }> = [
-      { color: displayProcessor(min).color ?? FALLBACK_COLOR, percent: 0 },
+      { color: displayProcessor(min).color ?? baseColor, percent: 0 },
     ];
 
     for (const threshold of thresholds) {
@@ -51,15 +43,15 @@ export function buildGradientColors(
     return result;
   }
 
-  if (colorMode.isContinuous && colorMode.getColors && !forSegment) {
-    // Handle continuous color modes first
+  // Handle continuous color modes before other by-value modes
+  if (colorMode.isContinuous && colorMode.getColors) {
     const colors = colorMode.getColors(theme);
     return colors.map((color, idx) => ({ color, percent: idx / (colors.length - 1) }));
   }
 
+  // For value-based colors, we want to stay more true to the specific color,
+  // so a radial gradient that adds a bit of light and shade works best
   if (colorMode.isByValue) {
-    // For value based colors we want to stay more true to the specific color
-    // So a radial gradient that adds a bit of light and shade works best
     const darkerColor = tinycolor(baseColor).darken(5);
     const lighterColor = tinycolor(baseColor).spin(20).lighten(10);
 
@@ -73,8 +65,7 @@ export function buildGradientColors(
     ];
   }
 
-  // For value based colors we want to stay more true to the specific color
-  // So a radial gradient that adds a bit of light and shade works best
+  // for fixed colors and other modes, we create a simple two-color gradient
   // we set the highest contrast color second based on the theme.
   const darkerColor = tinycolor(baseColor).spin(-20).darken(5);
   const lighterColor = tinycolor(baseColor).saturate(20).spin(20).brighten(10);
@@ -89,13 +80,74 @@ export function buildGradientColors(
       ];
 }
 
-export function getEndpointColors(gradientStops: GradientStop[], percent = 0): [string, string] {
+function clamp(value: number, min = 0, max = 1) {
+  if (process.env.NODE_ENV !== 'production') {
+    if (value < min || value > max) {
+      console.error(`The value provided ${value} is out of range [${min}, ${max}].`);
+    }
+  }
+
+  return Math.min(Math.max(min, value), max);
+}
+
+/**
+ * @alpha - perhaps this should go in colorManipulator.ts
+ * Given color stops (each with a color and percentage 0..1) returns the color at a given percentage.
+ * Uses tinycolor.mix for interpolation.
+ * @params stops - array of color stops (percentages 0..1)
+ * @params percent - percentage 0..1
+ * @returns color at the given percentage
+ */
+export function colorAtGradientPercent(stops: GradientStop[], percent: number): tinycolor.Instance {
+  if (!stops || stops.length < 2) {
+    throw new Error('colorAtGradientPercent requires at least two color stops');
+  }
+
+  // normalize and sort stops by percent
+  const sorted = stops
+    .map((s) => ({ color: s.color, percent: clamp(s.percent, 0, 1) }))
+    .sort((a, b) => a.percent - b.percent);
+
+  // percent outside range
+  if (percent <= sorted[0].percent) {
+    return tinycolor(sorted[0].color);
+  }
+  if (percent >= sorted[sorted.length - 1].percent) {
+    return tinycolor(sorted[sorted.length - 1].color);
+  }
+
+  // find surrounding stops
+  let left = sorted[0];
+  let right = sorted[sorted.length - 1];
+  for (let i = 1; i < sorted.length; i++) {
+    if (percent <= sorted[i].percent) {
+      left = sorted[i - 1];
+      right = sorted[i];
+      break;
+    }
+  }
+
+  const range = right.percent - left.percent;
+  const t = range === 0 ? 0 : (percent - left.percent) / range; // 0..1
+
+  // tinycolor.mix expects amount as percentage of the second color
+  const mixed = tinycolor.mix(left.color, right.color, t * 100);
+
+  // return hex6 if opaque, hex8 if has alpha
+  return mixed;
+}
+
+export function getEndpointColors(gradientStops: GradientStop[], percent = 1): [string, string] {
+  if (gradientStops.length === 0) {
+    throw new Error('getEndpointColors requires at least one color stop');
+  }
+
   const startColor = gradientStops[0].color;
   let endColor = gradientStops[gradientStops.length - 1].color;
 
   // if we have a percentageFilled, use it to get a the correct end color based on where the bar terminates
   if (gradientStops.length >= 2) {
-    const endColorByPercentage = colorManipulator.colorAtGradientPercent(gradientStops, percent);
+    const endColorByPercentage = colorAtGradientPercent(gradientStops, percent);
     endColor =
       endColorByPercentage.getAlpha() === 1 ? endColorByPercentage.toHexString() : endColorByPercentage.toHex8String();
   }
@@ -109,14 +161,18 @@ export function getGradientCss(gradientStops: GradientStop[], shape: RadialShape
     : `linear-gradient(90deg, ${colorStrings.join(', ')})`;
 }
 
+// the theme does not make the full palette available to us, and we
+// don't want transparent colors which our grays usually have.
+const GRAY_05 = '#111217';
+const GRAY_90 = '#fbfbfb';
 const CONTRAST_THRESHOLD_MAX = 4.5;
 const getGuideDotColor = (color: string): string => {
-  const darkColor = '#111217'; // gray05
-  const lightColor = '#fbfbfb'; // gray90
+  const darkColor = GRAY_05;
+  const lightColor = GRAY_90;
   return colorManipulator.getContrastRatio(darkColor, color) >= CONTRAST_THRESHOLD_MAX ? darkColor : lightColor;
 };
 
-export function getGuideDotColors(gradientStops: GradientStop[], percent = 0): [string, string] {
+export function getGuideDotColors(gradientStops: GradientStop[], percent: number): [string, string] {
   const [startColor, endColor] = getEndpointColors(gradientStops, percent);
   return [getGuideDotColor(startColor), getGuideDotColor(endColor)];
 }

packages/grafana-ui/src/components/RadialGauge/effects.tsx

@@ -1,4 +1,4 @@
-import { GaugeDimensions } from './utils';
+import { RadialGaugeDimensions } from './types';
 
 export interface GlowGradientProps {
   id: string;
@@ -27,7 +27,7 @@ const CENTER_GLOW_OPACITY = 0.15;
 
 export function CenterGlowGradient({ gaugeId, color }: { gaugeId: string; color: string }) {
   return (
-    <radialGradient id={`circle-glow-${gaugeId}`} r={'50%'} fr={'0%'}>
+    <radialGradient id={`circle-glow-${gaugeId}`} r="50%" fr="0%">
       <stop offset="0%" stopColor={color} stopOpacity={CENTER_GLOW_OPACITY} />
       <stop offset="90%" stopColor={color} stopOpacity={0} />
     </radialGradient>
@@ -35,7 +35,7 @@ export function CenterGlowGradient({ gaugeId, color }: { gaugeId: string; color:
 }
 
 export interface CenterGlowProps {
-  dimensions: GaugeDimensions;
+  dimensions: RadialGaugeDimensions;
   gaugeId: string;
   color?: string;
 }
@@ -46,7 +46,7 @@ export function MiddleCircleGlow({ dimensions, gaugeId, color }: CenterGlowProps
   return (
     <>
       <defs>
-        <radialGradient id={gradientId} r={'50%'} fr={'0%'}>
+        <radialGradient id={gradientId} r="50%" fr="0%">
           <stop offset="0%" stopColor={color} stopOpacity={CENTER_GLOW_OPACITY} />
           <stop offset="90%" stopColor={color} stopOpacity={0} />
         </radialGradient>

packages/grafana-ui/src/components/RadialGauge/types.ts

@@ -0,0 +1,26 @@
+export type RadialGradientMode = 'none' | 'auto';
+export type RadialTextMode = 'auto' | 'value_and_name' | 'value' | 'name' | 'none';
+export type RadialShape = 'circle' | 'gauge';
+
+export interface RadialGaugeDimensions {
+  margin: number;
+  radius: number;
+  centerX: number;
+  centerY: number;
+  barWidth: number;
+  endAngle?: number;
+  barIndex: number;
+  thresholdsBarRadius: number;
+  thresholdsBarWidth: number;
+  thresholdsBarSpacing: number;
+  scaleLabelsFontSize: number;
+  scaleLabelsSpacing: number;
+  scaleLabelsRadius: number;
+  gaugeBottomY: number;
+}
+
+/** @alpha - perhaps this should go in @grafana/data */
+export interface GradientStop {
+  color: string;
+  percent: number;
+}

packages/grafana-ui/src/components/RadialGauge/utils.test.ts

@@ -1,24 +1,111 @@
-import { FieldDisplay } from '@grafana/data';
+import { DataFrameView, FieldDisplay } from '@grafana/data';
 
 import type { RadialGaugeProps } from './RadialGauge';
-import { calculateDimensions, toRad, getValueAngleForValue } from './utils';
+import { RadialGaugeDimensions } from './types';
+import {
+  calculateDimensions,
+  toRad,
+  getValueAngleForValue,
+  drawRadialArcPath,
+  getFieldConfigMinMax,
+  getFieldDisplayProcessor,
+  getAngleBetweenSegments,
+  getOptimalSegmentCount,
+} from './utils';
 
 describe('RadialGauge utils', () => {
-  function calc(overrides: Partial<RadialGaugeProps & { barIndex: number }> = {}) {
-    return calculateDimensions(
-      overrides.width ?? 200,
-      overrides.height ?? 200,
-      overrides.shape === 'gauge' ? 110 : 360,
-      overrides.glowBar ?? false,
-      overrides.roundedBars ?? false,
-      overrides.barWidthFactor ?? 0.4,
-      overrides.barIndex ?? 0,
-      overrides.thresholdsBar ?? false,
-      overrides.showScaleLabels ?? false
-    );
-  }
+  describe('getFieldDisplayProcessor', () => {
+    it('should return display processor from view when available', () => {
+      const mockProcessor = jest.fn();
+      const mockView = {
+        getFieldDisplayProcessor: jest.fn().mockReturnValue(mockProcessor),
+      } as unknown as DataFrameView;
+
+      const fieldDisplay: FieldDisplay = {
+        display: { numeric: 50, text: '50', color: 'blue' },
+        field: {},
+        view: mockView,
+        colIndex: 0,
+        rowIndex: 0,
+        name: 'test',
+        getLinks: () => [],
+        hasLinks: false,
+      };
+
+      const dp = getFieldDisplayProcessor(fieldDisplay);
+      expect(dp).toBe(mockProcessor);
+      expect(mockView.getFieldDisplayProcessor).toHaveBeenCalledWith(0);
+    });
+
+    it('should return default display processor when view is not available', () => {
+      const fieldDisplay: FieldDisplay = {
+        display: { numeric: 50, text: '50', color: 'blue' },
+        field: {},
+        view: undefined,
+        colIndex: 0,
+        rowIndex: 0,
+        name: 'test',
+        getLinks: () => [],
+        hasLinks: false,
+      };
+
+      const dp = getFieldDisplayProcessor(fieldDisplay);
+      expect(dp).toBeDefined();
+      expect(typeof dp).toBe('function');
+    });
+  });
+
+  describe('getFieldConfigMinMax', () => {
+    it('should return min and max from field config when defined', () => {
+      const fieldDisplay: FieldDisplay = {
+        display: { numeric: 50, text: '50', color: 'blue' },
+        field: { min: 10, max: 90 },
+        view: undefined,
+        colIndex: 0,
+        rowIndex: 0,
+        name: 'test',
+        getLinks: () => [],
+        hasLinks: false,
+      };
+
+      const [min, max] = getFieldConfigMinMax(fieldDisplay);
+      expect(min).toBe(10);
+      expect(max).toBe(90);
+    });
+
+    it('should return default min and max when not defined in field config', () => {
+      const fieldDisplay: FieldDisplay = {
+        display: { numeric: 50, text: '50', color: 'blue' },
+        field: {},
+        view: undefined,
+        colIndex: 0,
+        rowIndex: 0,
+        name: 'test',
+        getLinks: () => [],
+        hasLinks: false,
+      };
+
+      const [min, max] = getFieldConfigMinMax(fieldDisplay);
+      expect(min).toBe(0);
+      expect(max).toBe(100);
+    });
+  });
 
   describe('calculateDimensions', () => {
+    function calc(overrides: Partial<RadialGaugeProps & { barIndex: number }> = {}) {
+      return calculateDimensions(
+        overrides.width ?? 200,
+        overrides.height ?? 200,
+        overrides.shape === 'gauge' ? 110 : 360,
+        overrides.glowBar ?? false,
+        overrides.roundedBars ?? false,
+        overrides.barWidthFactor ?? 0.4,
+        overrides.barIndex ?? 0,
+        overrides.thresholdsBar ?? false,
+        overrides.showScaleLabels ?? false
+      );
+    }
+
     it('should calculate basic dimensions for a square gauge', () => {
       const result = calc();
 
@@ -194,4 +281,86 @@ describe('RadialGauge utils', () => {
       expect(result.angle).toBe(240);
     });
   });
+
+  describe('drawRadialArcPath', () => {
+    const defaultDims: RadialGaugeDimensions = Object.freeze({
+      centerX: 100,
+      centerY: 100,
+      radius: 80,
+      barWidth: 20,
+      margin: 0,
+      barIndex: 0,
+      thresholdsBarWidth: 0,
+      thresholdsBarSpacing: 0,
+      thresholdsBarRadius: 0,
+      scaleLabelsFontSize: 0,
+      scaleLabelsSpacing: 0,
+      scaleLabelsRadius: 0,
+      gaugeBottomY: 0,
+    });
+
+    it.each([
+      { description: 'quarter arc', startAngle: 0, endAngle: 90 },
+      { description: 'half arc', startAngle: 0, endAngle: 180 },
+      { description: 'three quarter arc', startAngle: 0, endAngle: 270 },
+      { description: 'rounded bars', startAngle: 0, endAngle: 270, roundedBars: true },
+      { description: 'wide bar width', startAngle: 0, endAngle: 180, dimensions: { barWidth: 50 } },
+      { description: 'narrow bar width', startAngle: 0, endAngle: 180, dimensions: { barWidth: 5 } },
+      { description: 'narrow radius', startAngle: 0, endAngle: 180, dimensions: { radius: 50 } },
+      {
+        description: 'center x and y',
+        startAngle: 0,
+        endAngle: 360,
+        roundedBars: true,
+        dimensions: { centerX: 150, centerY: 200 },
+      },
+    ])(`should draw correct path for $description`, ({ startAngle, endAngle, dimensions, roundedBars }) => {
+      const path = drawRadialArcPath(startAngle, endAngle, { ...defaultDims, ...dimensions }, roundedBars);
+      expect(path).toMatchSnapshot();
+    });
+
+    describe('edge cases', () => {
+      it('should adjust 360deg or greater  arcs to avoid SVG rendering issues', () => {
+        expect(drawRadialArcPath(0, 360, defaultDims)).toEqual(drawRadialArcPath(0, 359.99, defaultDims));
+        expect(drawRadialArcPath(0, 380, defaultDims)).toEqual(drawRadialArcPath(0, 380, defaultDims));
+      });
+
+      it('should throw an error if inner radius collapses to zero or below', () => {
+        const smallRadiusDims = { ...defaultDims, radius: 5, barWidth: 20 };
+        expect(() => drawRadialArcPath(0, 180, smallRadiusDims)).toThrow(
+          'Inner radius collapsed to zero or below, cannot draw radial arc path'
+        );
+      });
+    });
+  });
+
+  describe('getAngleBetweenSegments', () => {
+    it('should calculate angle between segments based on spacing and count', () => {
+      expect(getAngleBetweenSegments(2, 10, 360)).toBe(48);
+      expect(getAngleBetweenSegments(5, 15, 180)).toBe(40);
+    });
+  });
+
+  describe('getOptimalSegmentCount', () => {
+    it('should adjust segment count based on dimensions and spacing', () => {
+      const dimensions: RadialGaugeDimensions = {
+        centerX: 100,
+        centerY: 100,
+        radius: 80,
+        barWidth: 20,
+        margin: 0,
+        barIndex: 0,
+        thresholdsBarWidth: 0,
+        thresholdsBarSpacing: 0,
+        thresholdsBarRadius: 0,
+        scaleLabelsFontSize: 0,
+        scaleLabelsSpacing: 0,
+        scaleLabelsRadius: 0,
+        gaugeBottomY: 0,
+      };
+
+      expect(getOptimalSegmentCount(dimensions, 2, 10, 360)).toBe(8);
+      expect(getOptimalSegmentCount(dimensions, 1, 5, 360)).toBe(5);
+    });
+  });
 });

packages/grafana-ui/src/components/RadialGauge/utils.ts

@@ -1,11 +1,34 @@
-import { FieldDisplay } from '@grafana/data';
+import { FieldDisplay, getDisplayProcessor } from '@grafana/data';
 
-export function getValueAngleForValue(fieldDisplay: FieldDisplay, startAngle: number, endAngle: number) {
-  const angleRange = (360 % (startAngle === 0 ? 1 : startAngle)) + endAngle;
+import { RadialGaugeDimensions } from './types';
+
+export function getFieldDisplayProcessor(displayValue: FieldDisplay) {
+  if (displayValue.view && displayValue.colIndex != null) {
+    const dp = displayValue.view.getFieldDisplayProcessor(displayValue.colIndex);
+    if (dp) {
+      return dp;
+    }
+  }
+
+  return getDisplayProcessor();
+}
+
+export function getFieldConfigMinMax(fieldDisplay: FieldDisplay) {
   const min = fieldDisplay.field.min ?? 0;
   const max = fieldDisplay.field.max ?? 100;
+  return [min, max];
+}
 
-  let angle = ((fieldDisplay.display.numeric - min) / (max - min)) * angleRange;
+export function getValueAngleForValue(
+  fieldDisplay: FieldDisplay,
+  startAngle: number,
+  endAngle: number,
+  value = fieldDisplay.display.numeric
+) {
+  const [min, max] = getFieldConfigMinMax(fieldDisplay);
+  const angleRange = (360 % (startAngle === 0 ? 1 : startAngle)) + endAngle;
+
+  let angle = ((value - min) / (max - min)) * angleRange;
 
   if (angle > angleRange) {
     angle = angleRange;
@@ -26,24 +49,19 @@ export function toRad(angle: number) {
   return ((angle - 90) * Math.PI) / 180;
 }
 
-export interface GaugeDimensions {
-  margin: number;
-  radius: number;
-  centerX: number;
-  centerY: number;
-  barWidth: number;
-  endAngle?: number;
-  barIndex: number;
-  thresholdsBarRadius: number;
-  thresholdsBarWidth: number;
-  thresholdsBarSpacing: number;
-  showScaleLabels?: boolean;
-  scaleLabelsFontSize: number;
-  scaleLabelsSpacing: number;
-  scaleLabelsRadius: number;
-  gaugeBottomY: number;
-}
-
+/**
+ * returns the calculated dimensions for the radial gauge
+ * @param width
+ * @param height
+ * @param endAngle
+ * @param glow
+ * @param roundedBars
+ * @param barWidthFactor
+ * @param barIndex
+ * @param thresholdBar
+ * @param showScaleLabels
+ * @returns {RadialGaugeDimensions}
+ */
 export function calculateDimensions(
   width: number,
   height: number,
@@ -54,7 +72,7 @@ export function calculateDimensions(
   barIndex: number,
   thresholdBar?: boolean,
   showScaleLabels?: boolean
-): GaugeDimensions {
+): RadialGaugeDimensions {
   const yMaxAngle = endAngle > 180 ? 180 : endAngle;
   let margin = 0;
 
@@ -157,26 +175,32 @@ export function toCartesian(centerX: number, centerY: number, radius: number, an
 }
 
 export function drawRadialArcPath(
-  angle: number,
-  arcLengthDeg: number,
-  dimensions: GaugeDimensions,
+  startAngle: number,
+  endAngle: number,
+  dimensions: RadialGaugeDimensions,
   roundedBars?: boolean
 ): string {
   const { radius, centerX, centerY, barWidth } = dimensions;
 
-  if (arcLengthDeg === 360) {
-    // For some reason a 100% full arc cannot be rendered
-    arcLengthDeg = 359.99;
+  // For some reason a 100% full arc cannot be rendered
+  if (endAngle >= 360) {
+    endAngle = 359.99;
   }
 
-  const startRadians = toRad(angle);
-  const endRadians = toRad(angle + arcLengthDeg);
+  const startRadians = toRad(startAngle);
+  const endRadians = toRad(startAngle + endAngle);
 
-  const largeArc = arcLengthDeg > 180 ? 1 : 0;
+  const largeArc = endAngle > 180 ? 1 : 0;
 
   const outerR = radius + barWidth / 2;
   const innerR = Math.max(0, radius - barWidth / 2);
+  if (innerR <= 0) {
+    throw new Error('Inner radius collapsed to zero or below, cannot draw radial arc path');
+  }
 
+  // get points for both an inner and outer arc. we draw
+  // the arc entirely with a path's fill instead of using stroke
+  // so that it can be used as a clip-path.
   const ox1 = centerX + outerR * Math.cos(startRadians);
   const oy1 = centerY + outerR * Math.sin(startRadians);
   const ox2 = centerX + outerR * Math.cos(endRadians);
@@ -187,6 +211,7 @@ export function drawRadialArcPath(
   const ix2 = centerX + innerR * Math.cos(endRadians);
   const iy2 = centerY + innerR * Math.sin(endRadians);
 
+  // calculate the cap width in case we're drawing rounded bars
   const capR = barWidth / 2;
 
   const pathParts = [
@@ -209,27 +234,44 @@ export function drawRadialArcPath(
     // rounded end cap: small arc connecting outer end to inner end
     pathParts.push('A', capR, capR, 0, 0, 1, ix2, iy2);
   } else {
-    // straight line to inner end
+    // straight line to inner end (square butt)
     pathParts.push('L', ix2, iy2);
   }
 
-  if (innerR <= 0) {
-    // if inner radius collapsed to center, line to center and close
-    pathParts.push('L', centerX, centerY, 'Z');
+  // inner arc from end back to start (counter-clockwise)
+  pathParts.push('A', innerR, innerR, 0, largeArc, 0, ix1, iy1);
+
+  if (roundedBars) {
+    // rounded start cap: small arc connecting inner start back to outer start
+    pathParts.push('A', capR, capR, 0, 0, 1, ox1, oy1);
   } else {
-    // inner arc from end back to start (counter-clockwise)
-    pathParts.push('A', innerR, innerR, 0, largeArc, 0, ix1, iy1);
-
-    if (roundedBars) {
-      // rounded start cap: small arc connecting inner start back to outer start
-      pathParts.push('A', capR, capR, 0, 0, 1, ox1, oy1);
-    } else {
-      // straight line back to outer start
-      pathParts.push('L', ox1, oy1);
-    }
-
-    pathParts.push('Z');
+    // straight line back to outer start (square butt)
+    pathParts.push('L', ox1, oy1);
   }
 
+  pathParts.push('Z');
+
   return pathParts.join(' ');
 }
+
+export function getAngleBetweenSegments(segmentSpacing: number, segmentCount: number, range: number) {
+  // Max spacing is 8 degrees between segments
+  // Changing this constant could be considered a breaking change
+  const maxAngleBetweenSegments = Math.max(range / 1.5 / segmentCount, 2);
+  return segmentSpacing * maxAngleBetweenSegments;
+}
+
+export function getOptimalSegmentCount(
+  dimensions: RadialGaugeDimensions,
+  segmentSpacing: number,
+  segmentCount: number,
+  range: number
+) {
+  const angleBetweenSegments = getAngleBetweenSegments(segmentSpacing, segmentCount, range);
+
+  const innerRadius = dimensions.radius - dimensions.barWidth / 2;
+  const circumference = Math.PI * innerRadius * 2 * (range / 360);
+  const maxSegments = Math.floor(circumference / (angleBetweenSegments + 3));
+
+  return Math.min(maxSegments, segmentCount);
+}