Properly render gradients when strokeScaling=false

Author: adroitwhiz

src/item/Item.js

@@ -4279,16 +4279,16 @@ new function() { // Injection scope for hit-test functions shared with project
      * Not defined in Path as it is required by other classes too,
      * e.g. PointText.
      */
-    _setStyles: function(ctx, param, viewMatrix) {
+    _setStyles: function(ctx, param, viewMatrix, strokeMatrix) {
         // We can access internal properties since we're only using this on
         // items without children, where styles would be merged.
         var style = this._style,
             matrix = this._matrix;
         if (style.hasFill()) {
-            ctx.fillStyle = style.getFillColor().toCanvasStyle(ctx, matrix);
+            ctx.fillStyle = style.getFillColor().toCanvasStyle(ctx, matrix, strokeMatrix);
         }
         if (style.hasStroke()) {
-            ctx.strokeStyle = style.getStrokeColor().toCanvasStyle(ctx, matrix);
+            ctx.strokeStyle = style.getStrokeColor().toCanvasStyle(ctx, matrix, strokeMatrix);
             ctx.lineWidth = style.getStrokeWidth();
             var strokeJoin = style.getStrokeJoin(),
                 strokeCap = style.getStrokeCap(),

src/item/Shape.js

@@ -261,7 +261,7 @@ var Shape = Item.extend(/** @lends Shape# */{
             ctx.closePath();
         }
         if (!dontPaint && (hasFill || hasStroke)) {
-            this._setStyles(ctx, param, viewMatrix);
+            this._setStyles(ctx, param, viewMatrix, strokeMatrix);
             if (hasFill) {
                 ctx.fill(style.getFillRule());
                 ctx.shadowColor = 'rgba(0,0,0,0)';

src/path/CompoundPath.js

@@ -311,7 +311,7 @@ var CompoundPath = PathItem.extend(/** @lends CompoundPath# */{
             children[i].draw(ctx, param, strokeMatrix);
 
         if (!param.clip) {
-            this._setStyles(ctx, param, viewMatrix);
+            this._setStyles(ctx, param, viewMatrix, strokeMatrix);
             var style = this._style;
             if (style.hasFill()) {
                 ctx.fill(style.getFillRule());

src/path/Path.js

@@ -2321,7 +2321,7 @@ new function() { // Scope for drawing
             if (!dontPaint && (hasFill || hasStroke)) {
                 // If the path is part of a compound path or doesn't have a fill
                 // or stroke, there is no need to continue.
-                this._setStyles(ctx, param, viewMatrix);
+                this._setStyles(ctx, param, viewMatrix, strokeMatrix);
                 if (hasFill) {
                     ctx.fill(style.getFillRule());
                     // If shadowColor is defined, clear it after fill, so it

src/style/Color.js

@@ -899,8 +899,11 @@ var Color = Base.extend(new function() {
                         + components.join(',') + ')';
         },
 
-        toCanvasStyle: function(ctx, matrix) {
-            if (this._canvasStyle)
+        toCanvasStyle: function(ctx, matrix, strokeMatrix) {
+            // strokeMatrix can change without triggering _changed here, so we
+            // can't use a cached gradient here.
+            var strokeMayChange = this._type === 'gradient' && strokeMatrix;
+            if (this._canvasStyle && !strokeMayChange)
                 return this._canvasStyle;
             // Normal colors are simply represented by their CSS string.
             if (this._type !== 'gradient')
@@ -923,6 +926,12 @@ var Color = Base.extend(new function() {
                 if (highlight)
                     highlight = inverse._transformPoint(highlight);
             }
+            if (strokeMatrix) {
+                origin = strokeMatrix._transformPoint(origin);
+                destination = strokeMatrix._transformPoint(destination);
+                if (highlight)
+                    highlight = strokeMatrix._transformPoint(highlight);
+            }
             if (gradient._radial) {
                 var radius = destination.getDistance(origin);
                 if (highlight) {
@@ -948,7 +957,12 @@ var Color = Base.extend(new function() {
                         offset == null ? i / (l - 1) : offset,
                         stop._color.toCanvasStyle());
             }
-            return this._canvasStyle = canvasGradient;
+            // Don't store gradients that may change in the cache.
+            // If we cached a gradient that was transformed by strokeMatrix
+            // then set strokeScaling to true, then the transformed gradient
+            // could get "stuck" in the cache.
+            if (!strokeMayChange) this._canvasStyle = canvasGradient;
+            return canvasGradient;
         },
 
         /**