fpvectorial: Fix rendering of radial gradients

components/fpvectorial/fpvectorial.pas

@@ -4307,17 +4307,9 @@ var
   lDist: Double;
   lColor: TFPColor;
 
-  function GradientValue_to_px(AValue: Double; AUnit: TvCoordinateUnit; AIsY: Boolean): Integer;
+  function GradientValue_to_px(AValue: Double; AUnit: TvCoordinateUnit; ASideLen: Integer; AIsY: Boolean): Integer;
-  var
-    lSideLen: Integer;
   begin
     Result := 0;
-
-    if AIsY then
-      lSideLen := (ARect.Bottom-ARect.Top)
-    else
-      lSideLen := (ARect.Right-ARect.Left);
-
     case AUnit of
       vcuDocumentUnit:
         if AIsY then
@@ -4325,7 +4317,7 @@ var
         else
           Result := CoordToCanvasX(AValue, ARenderInfo.DestX, ARenderInfo.MulX);
       vcuPercentage:
-        Result := Round(lSideLen * AValue);
+        Result := Round(ASideLen * AValue);
     end;
   end;
 
@@ -4363,10 +4355,10 @@ begin
   lAspectRatio := lHeight/lWidth;
 
   // Calculate center of outer-most gradient circle
-  lGradient_cx_px := GradientValue_to_px(Brush.Gradient_cx, Brush.Gradient_cx_Unit, False);
+  lGradient_cx_px := GradientValue_to_px(Brush.Gradient_cx, Brush.Gradient_cx_Unit, lWidth, False);
-  lGradient_cy_px := GradientValue_to_px(Brush.Gradient_cy, Brush.Gradient_cy_Unit, True);
+  lGradient_cy_px := GradientValue_to_px(Brush.Gradient_cy, Brush.Gradient_cy_Unit, lHeight, True);
   // Calculate radius of outer-most gradient circle, relative the width
-  lGradient_r_px := GradientValue_to_px(Brush.Gradient_r, Brush.Gradient_r_Unit, False);
+  lGradient_r_px := GradientValue_to_px(Brush.Gradient_r, Brush.Gradient_r_Unit, lWidth, false);
   { -- not implemented, yet
   lGradient_fx_px := GradientValue_to_px(Brush.Gradient_fx, Brush.Gradient_fx_Unit, False);
   lGradient_fy_px := GradientValue_to_px(Brush.Gradient_fy, Brush.Gradient_fy_Unit, True);
@@ -4375,19 +4367,19 @@ begin
   // pixel-by-pixel version
   for i := 0 to lWidth-1 do
   begin
-    for J := 0 to lHeight-1 do
+    for j := 0 to lHeight-1 do
     begin
       lx := ARect.Left + i;
       ly := ARect.Top + j;
       if not IsPointInPolygon(lx, ly, APoints) then Continue;
 
-      // distance of current point (i, j) to gradient center, corrected for aspect ratio
+      // distance of current point (i, j) to gradient center, correct for aspect ratio
       lDist := sqrt(sqr(i - lGradient_cx_px) + sqr((j - lGradient_cy_px)/lAspectRatio));
+//      lDist := sqrt(sqr(i-lGradient_cx_px)+sqr(j-lGradient_cy_px));
       lDist := lDist / lGradient_r_px;
       lDist := Min(Max(0, lDist), 1);
-
-      // Color for point (lx, ly)
       lColor := Distance_To_RadialGradientColor(lDist);
+
       ADest.Colors[lx, ly] := AlphaBlendColor(ADest.Colors[lx, ly], lColor);
     end;
   end;

components/fpvectorial/tests/vt_gradients.inc

@@ -48,4 +48,15 @@ Tree.Items.AddChildObject(node, 'Rounded rectangle',
 Tree.Items.AddChildObject(node, 'Polygon',
   TRenderParams.Create(@Render_Shape, 'polygon_gradientradial.png', $0504));
 
+node := Tree.Items.AddChild(mainnode, 'radial off-center');
+Tree.Items.AddChildObject(node, 'Circle',
+  TRenderParams.Create(@Render_Shape, 'circle_gradientradial_offc.png', $0105));
+Tree.Items.AddChildObject(node, 'Ellipse',
+  TRenderParams.Create(@Render_Shape, 'ellipse_gradientradial_offc.png', $0205));
+Tree.Items.AddChildObject(node, 'Rectangle',
+  TRenderParams.Create(@Render_Shape, 'rect_gradientradial_offc.png', $0305));
+Tree.Items.AddChildObject(node, 'Rounded rectangle',
+  TRenderParams.Create(@Render_Shape, 'rounded_rect_gradientradial_offc.png', $0405));
+Tree.Items.AddChildObject(node, 'Polygon',
+  TRenderParams.Create(@Render_Shape, 'polygon_gradientradial_offc.png', $0505));
 

components/fpvectorial/tests/vtmain.pas

@@ -440,7 +440,8 @@ procedure TMainForm.Render_Shape(APage: TvVectorialPage;
                             $00000001 --> horizontal gradient
                             $00000002 --> vertical gradient
                             $00000003 --> linear gradient
-                            $00000004 --> radial gradient
+                            $00000004 --> radial gradient (centered)
+                            $00000005 --> radial gradient (off-center)
   AIntParam and $0000FF00 = $00000100 --> circle
                             $00000200 --> ellipse
                             $00000300 --> rectangle
@@ -465,7 +466,8 @@ begin
     $00000001: ent.Brush := StdHorizGradientBrush(colYellow, colRed);
     $00000002: ent.Brush := StdVertGradientBrush(colYellow, colRed);
     $00000003: ent.Brush := StdLinearGradientBrush(colYellow, colRed);
-    $00000004: ent.Brush := StdRadialGradientBrush(colYellow, colRed);
+    $00000004: ent.Brush := StdRadialGradientBrush(colYellow, colRed, 0.5, 0.5, 0.5);
+    $00000005: ent.Brush := StdRadialGradientBrush(colYellow, colRed, 0.25, 0.25, 0.75);
     else raise Exception.Create('Brush not supported');
   end;
   case AIntParam and $000F0000 of
@@ -616,7 +618,8 @@ begin
     $00000001: obj.Brush := StdHorizGradientBrush(colYellow, colRed);
     $00000002: obj.Brush := StdVertGradientBrush(colYellow, colRed);
     $00000003: obj.Brush := StdLinearGradientBrush(colYellow, colRed);
-    $00000004: obj.Brush := StdRadialGradientBrush(colYellow, colRed);
+    $00000004: obj.Brush := StdRadialGradientBrush(colYellow, colRed, 0.5, 0.5, 0.5);
+    $00000005: obj.Brush := StdRadialGradientBrush(colYellow, colRed, 0.25, 0.25, 0.75);
     else raise Exception.Create('Brush not supported');
   end;
   case AIntParam and $000F0000 of
@@ -646,7 +649,8 @@ begin
     $00000001: obj.Brush := StdHorizGradientBrush(colBlue, colWhite);
     $00000002: obj.Brush := StdVertGradientBrush(colBlue, colWhite);
     $00000003: obj.Brush := StdLinearGradientBrush(colBlue, colWhite);
-    $00000004: obj.Brush := StdRadialGradientBrush(colBlue, colWhite);
+    $00000004: obj.Brush := StdRadialGradientBrush(colBlue, colWhite, 0.5, 0.5, 0.5);
+    $00000005: obj.Brush := StdRadialGradientBrush(colBlue, colWhite, 0.25, 0.25, 0.75);
     else raise Exception.Create('Brush not supported');
   end;
   case AIntParam and $00000F00 of

components/fpvectorial/tests/vtprimitives.pas

@@ -37,7 +37,7 @@ function StdSolidBrush(AColor: TFPColor): TvBrush;
 function StdHorizGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
 function StdVertGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
 function StdLinearGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
-function StdRadialGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
+function StdRadialGradientBrush(AColor1, AColor2: TFPColor; CX, CY, R: Double): TvBrush;
 function StdPen(AColor: TFPColor; AWidth: Integer): TvPen;
 
 procedure Rotate(APage: TvVectorialPage; AShape: TvEntity; Angle: Double);
@@ -256,6 +256,30 @@ begin
   Result.Gradient_colors[1].Position := 1;
 end;
 
+function CreateRadialGradientBrush(CX, CY, R, FX, FY: Double;
+  AStartColor, AEndColor: TFPColor): TvBrush;
+begin
+  Result.Kind := bkRadialGradient;
+  Result.Gradient_cx := CX;
+  Result.Gradient_cy := CY;
+  Result.Gradient_r := R;
+  // Our renderer does not support a moving center --> put both centers at the same spot
+  Result.Gradient_fx := CX;
+  Result.Gradient_fy := CY;
+
+  Result.Gradient_cx_Unit := vcuPercentage;
+  Result.Gradient_cy_Unit := vcuPercentage;
+  Result.Gradient_r_Unit := vcuPercentage;
+  Result.Gradient_fx_Unit := vcuPercentage;
+  Result.Gradient_fy_Unit := vcuPercentage;
+
+  SetLength(Result.Gradient_colors, 2);
+  Result.Gradient_colors[0].Color := AStartColor;
+  Result.Gradient_colors[0].Position := 0;
+  Result.Gradient_colors[1].Color := AEndColor;
+  Result.Gradient_colors[1].Position := 1;
+end;
+                                          (*
 function CreateRadialGradientBrush(CX, CY, R, FX, FY: Double;
   AStartColor, AEndColor: TFPColor): TvBrush;
 begin
@@ -270,7 +294,7 @@ begin
   Result.Gradient_colors[0].Position := 0;
   Result.Gradient_colors[1].Color := AEndColor;
   Result.Gradient_colors[1].Position := 1;
-end;
+end;                                        *)
 
 
 { Pen }
@@ -438,9 +462,10 @@ begin
     AColor1, AColor2);
 end;
 
-function StdRadialGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
+function StdRadialGradientBrush(AColor1, AColor2: TFPColor;
+  CX, CY, R: Double): TvBrush;
 begin
-  Result := CreateRadialGradientBrush(0.5, 0.5, 0.5, 0.5, 0.5,
+  Result := CreateRadialGradientBrush(CX, CY, R, 0.5, 0.5,
     AColor1, AColor2);
 end;