feat: fill shader support

Author: farfromrefug

src/charting/data/LineRadarDataSet.ts

@@ -20,6 +20,11 @@ export abstract class LineRadarDataSet<T extends Entry> extends LineScatterCandl
      */
     protected mFillDrawable;
 
+    /**
+     * the shader to be used for filling the line surface
+     */
+    protected mFillShader;
+
     /**
      * transparency used for filling line surface
      */
@@ -49,6 +54,18 @@ export abstract class LineRadarDataSet<T extends Entry> extends LineScatterCandl
         this.mFillColor = color;
         this.mFillDrawable = null;
     }
+    /**
+     * Sets the shader that is used for filling the area below the line
+     *
+     * @param shader
+     */
+    public setFillShader(shader) {
+        this.mFillShader = shader;
+    }
+    public getFillShader() {
+        return this.mFillShader;
+    }
+
 
     public getFillDrawable() {
         return this.mFillDrawable;

src/charting/interfaces/datasets/ILineRadarDataSet.ts

@@ -18,6 +18,12 @@ export interface ILineRadarDataSet<T extends Entry> extends ILineScatterCandleRa
      * @return
      */
     getFillDrawable();
+    /**
+     * Returns the shader used for filling the area below the line.
+     *
+     * @return
+     */
+    getFillShader();
 
     /**
      * Returns the alpha value that is used for filling the line surface,

src/charting/renderer/LineChartRenderer.ts

@@ -478,9 +478,9 @@ export class LineChartRenderer extends LineRadarRenderer {
 
         const drawable = dataSet.getFillDrawable();
         if (drawable != null) {
-            this.drawFilledPathBitmap(c, spline, drawable);
+            this.drawFilledPathBitmap(c, spline, drawable, dataSet.getFillShader());
         } else {
-            this.drawFilledPath(c, spline, dataSet.getFillColor(), dataSet.getFillAlpha());
+            this.drawFilledPath(c, spline, dataSet.getFillColor(), dataSet.getFillAlpha(), dataSet.getFillShader());
         }
     }
 

src/charting/renderer/LineRadarRenderer.ts

@@ -24,7 +24,7 @@ export abstract class LineRadarRenderer extends LineScatterCandleRadarRenderer {
      * @param drawable
      */
     @profile
-    protected drawFilledPathBitmap(c: Canvas, filledPath: Path, drawable) {
+    protected drawFilledPathBitmap(c: Canvas, filledPath: Path, drawable, shader) {
         if (this.clipPathSupported()) {
             let save = c.save();
             // c.scale(1, 1/SCALE_FACTOR, 0, this.mViewPortHandler.contentBottom())
@@ -57,35 +57,40 @@ export abstract class LineRadarRenderer extends LineScatterCandleRadarRenderer {
      * @param fillAlpha
      */
     @profile
-    protected drawFilledPath(c: Canvas, filledPath: Path, fillColor: Color | string, fillAlpha: number = 1) {
+    protected drawFilledPath(c: Canvas, filledPath: Path, fillColor: Color | string, fillAlpha: number = 255, shader?) {
         let color = fillColor;
         if (fillAlpha < 255) {
-            fillColor = fillColor instanceof  Color ? fillColor : new Color(fillColor);
+            fillColor = fillColor instanceof Color ? fillColor : new Color(fillColor);
             color = new Color(fillAlpha, fillColor.r, fillColor.g, fillColor.b);
         }
 
+        // save
+        const previous = this.mRenderPaint.getStyle();
+        let previousColor = this.mRenderPaint.getColor();
+        let previousShader = this.mRenderPaint.getShader();
+
+        this.mRenderPaint.setStyle(Style.FILL);
+
+        if (shader) {
+            this.mRenderPaint.setColor('black');
+            this.mRenderPaint.setShader(shader);
+        } else {
+            this.mRenderPaint.setColor(color);
+
+        }
+
         if (this.clipPathSupported()) {
             let save = c.save();
-            // c.scale(1, 1/SCALE_FACTOR, 0, this.mViewPortHandler.contentBottom())
             c.clipPath(filledPath);
-
-            c.drawColor(color);
+            c.drawPaint(this.mRenderPaint);
             c.restoreToCount(save);
         } else {
-            // save
-            const previous = this.mRenderPaint.getStyle();
-            let previousColor = this.mRenderPaint.getColor();
-
-            // set
-            this.mRenderPaint.setStyle(Style.FILL);
-            this.mRenderPaint.setColor(color);
             this.drawPath(c, filledPath, this.mRenderPaint);
-            // c.drawPath(filledPath, this.mRenderPaint);
-
-            // restore
-            this.mRenderPaint.setColor(previousColor);
-            this.mRenderPaint.setStyle(previous);
         }
+        // restore
+        this.mRenderPaint.setColor(previousColor);
+        this.mRenderPaint.setShader(previousShader);
+        this.mRenderPaint.setStyle(previous);
     }
 
     /**