Added starting and ending anchor point properties for radial gradients.

NOUSguide · Mar 31, 2013 · f011567 · f011567
1 parent 67bb6fb
commit f011567
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Showing 4 changed files with 52 additions and 7 deletions.
diff --git a/documentation/changelog.markdown b/documentation/changelog.markdown
@@ -4,6 +4,7 @@
 
 ## Details
 - **New**: Added animation support for plot ranges, decimal values, and other properties.
+- **New**: Added starting and ending anchor point properties for radial gradients.
 - **Changed**: Changed the type of all axis and plot label formatters from `NSNumberFormatter` to `NSFormatter`.
 - **Changed**: Miscellaneous bug fixes and cleanup.
 

diff --git a/examples/CorePlotGallery/src/plots/GradientScatterPlot.m b/examples/CorePlotGallery/src/plots/GradientScatterPlot.m
@@ -145,11 +145,14 @@ -(void)renderInLayer:(CPTGraphHostingView *)layerHostingView withTheme:(CPTTheme
     plotSpace.globalYRange = globalYRange;
 
     // Add plot symbols
-    CPTMutableLineStyle *symbolLineStyle = [CPTMutableLineStyle lineStyle];
-    symbolLineStyle.lineColor = [CPTColor blackColor];
+    CPTGradient *symbolGradient = [CPTGradient gradientWithBeginningColor:[CPTColor colorWithComponentRed:0.75 green:0.75 blue:1.0 alpha:1.0]
+                                                              endingColor:[CPTColor blueColor]];
+    symbolGradient.gradientType = CPTGradientTypeRadial;
+    symbolGradient.startAnchor  = CPTPointMake(0.25, 0.75);
+
     CPTPlotSymbol *plotSymbol = [CPTPlotSymbol ellipsePlotSymbol];
-    plotSymbol.fill               = [CPTFill fillWithColor:[CPTColor blueColor]];
-    plotSymbol.lineStyle          = symbolLineStyle;
+    plotSymbol.fill               = [CPTFill fillWithGradient:symbolGradient];
+    plotSymbol.lineStyle          = nil;
     plotSymbol.size               = CGSizeMake(10.0, 10.0);
     dataSourceLinePlot.plotSymbol = plotSymbol;
 

diff --git a/framework/Source/CPTGradient.h b/framework/Source/CPTGradient.h
@@ -46,11 +46,26 @@ CPTGradientType;
     CGFunctionRef gradientFunction;
     CGFloat angle; // angle in degrees
     CPTGradientType gradientType;
+    CGPoint startAnchor;
+    CGPoint endAnchor;
 }
 
+/// @name Gradient Type
+/// @{
 @property (nonatomic, readonly, assign) CPTGradientBlendingMode blendingMode;
-@property (nonatomic, readwrite, assign) CGFloat angle;
 @property (nonatomic, readwrite, assign) CPTGradientType gradientType;
+/// @}
+
+/// @name Axial Gradients
+/// @{
+@property (nonatomic, readwrite, assign) CGFloat angle;
+/// @}
+
+/// @name Radial Gradients
+/// @{
+@property (nonatomic, readwrite, assign) CGPoint startAnchor;
+@property (nonatomic, readwrite, assign) CGPoint endAnchor;
+/// @}
 
 /// @name Factory Methods
 /// @{

diff --git a/framework/Source/CPTGradient.m b/framework/Source/CPTGradient.m
@@ -77,6 +77,16 @@ @implementation CPTGradient
  **/
 @synthesize gradientType;
 
+/** @property CGPoint startAnchor
+ *  @brief The anchor point for starting point of a radial gradient. Defaults to (@num{0.5}, @num{0.5}) which centers the gradient on the drawing rectangle.
+ **/
+@synthesize startAnchor;
+
+/** @property CGPoint endAnchor
+ *  @brief The anchor point for ending point of a radial gradient. Defaults to (@num{0.5}, @num{0.5}) which centers the gradient on the drawing rectangle.
+ **/
+@synthesize endAnchor;
+
 #pragma mark -
 #pragma mark Init/Dealloc
 
@@ -89,6 +99,8 @@ @implementation CPTGradient
  *  - @ref blendingMode = #CPTLinearBlendingMode
  *  - @ref angle = @num{0.0}
  *  - @ref gradientType = #CPTGradientTypeAxial
+ *  - @ref startAnchor = (@num{0.5}, @num{0.5})
+ *  - @ref endAnchor = (@num{0.5}, @num{0.5})
  *
  *  @return The initialized object.
  **/
@@ -101,6 +113,8 @@ -(id)init
 
         angle        = CPTFloat(0.0);
         gradientType = CPTGradientTypeAxial;
+        startAnchor  = CPTPointMake(0.5, 0.5);
+        endAnchor    = CPTPointMake(0.5, 0.5);
     }
     return self;
 }
@@ -151,6 +165,8 @@ -(id)copyWithZone:(NSZone *)zone
     copy.blendingMode  = self.blendingMode;
     copy->angle        = self->angle;
     copy->gradientType = self->gradientType;
+    copy->startAnchor  = self->startAnchor;
+    copy->endAnchor    = self->endAnchor;
 
     return copy;
 }
@@ -181,6 +197,8 @@ -(void)encodeWithCoder:(NSCoder *)coder
         [coder encodeInt:blendingMode forKey:@"CPTGradient.blendingMode"];
         [coder encodeCGFloat:angle forKey:@"CPTGradient.angle"];
         [coder encodeInt:gradientType forKey:@"CPTGradient.type"];
+        [coder encodeCPTPoint:self.startAnchor forKey:@"CPTPlotSymbol.startAnchor"];
+        [coder encodeCPTPoint:self.endAnchor forKey:@"CPTPlotSymbol.endAnchor"];
     }
     else {
         [NSException raise:NSInvalidArchiveOperationException format:@"Only supports NSKeyedArchiver coders"];
@@ -195,6 +213,8 @@ -(id)initWithCoder:(NSCoder *)coder
         gradientType      = (CPTGradientType)[coder decodeIntForKey : @"CPTGradient.type"];
         angle             = [coder decodeCGFloatForKey:@"CPTGradient.angle"];
         self.blendingMode = (CPTGradientBlendingMode)[coder decodeIntForKey : @"CPTGradient.blendingMode"];
+        startAnchor       = [coder decodeCPTPointForKey:@"CPTPlotSymbol.startAnchor"];
+        endAnchor         = [coder decodeCPTPointForKey:@"CPTPlotSymbol.endAnchor"];
 
         NSUInteger count = (NSUInteger)[coder decodeIntegerForKey : @"CPTGradient.elementCount"];
 
@@ -1015,7 +1035,6 @@ -(CGShadingRef)newAxialGradientInRect:(CGRect)rect
         endPoint   = CPTPointMake(CGRectGetMidX(rect) + deltaX, CGRectGetMidY(rect) + deltaY);
     }
 
-    // Calls to CoreGraphics
     CGShadingRef myCGShading = CGShadingCreateAxial(self.colorspace.cgColorSpace, startPoint, endPoint, gradientFunction, false, false);
 
     return myCGShading;
@@ -1027,7 +1046,14 @@ -(CGShadingRef)newRadialGradientInRect:(CGRect)rect context:(CGContextRef)contex
     CGFloat startRadius, endRadius;
     CGFloat scaleX, scaleY;
 
-    startPoint = endPoint = CPTPointMake( CGRectGetMidX(rect), CGRectGetMidY(rect) );
+    CGPoint theStartAnchor = self.startAnchor;
+
+    startPoint = CPTPointMake( fma( CGRectGetWidth(rect), theStartAnchor.x, CGRectGetMinX(rect) ),
+                               fma( CGRectGetHeight(rect), theStartAnchor.y, CGRectGetMinY(rect) ) );
+
+    CGPoint theEndAnchor = self.endAnchor;
+    endPoint = CPTPointMake( fma( CGRectGetWidth(rect), theEndAnchor.x, CGRectGetMinX(rect) ),
+                             fma( CGRectGetHeight(rect), theEndAnchor.y, CGRectGetMinY(rect) ) );
 
     startRadius = -CPTFloat(1.0);
     if ( CGRectGetHeight(rect) > CGRectGetWidth(rect) ) {