石英：无法创建带渐变填充的圆角矩形

我正要开始撕掉我的头发。我正在尝试创建一个包含圆角矩形区域的渐变填充。这是我在我的drawRect:代码：石英：无法创建带渐变填充的圆角矩形

CGContextRef ctx = UIGraphicsGetCurrentContext(); 
CGContextClearRect(ctx, rect); 

CGFloat c = BUBBLE_INSET + BUBBLE_CORNER_RADIUS; 

CGContextMoveToPoint(ctx, BUBBLE_INSET, c); 

CGContextAddArcToPoint(ctx, BUBBLE_INSET, BUBBLE_INSET, c, BUBBLE_INSET, BUBBLE_CORNER_RADIUS);  
CGContextAddLineToPoint(ctx, rect.size.width - c, BUBBLE_INSET); 
CGContextAddArcToPoint(ctx, rect.size.width - BUBBLE_INSET, BUBBLE_INSET, rect.size.width - BUBBLE_INSET, c, BUBBLE_CORNER_RADIUS); 
CGContextAddLineToPoint(ctx, rect.size.width - BUBBLE_INSET, rect.size.height - c); 
CGContextAddArcToPoint(ctx, rect.size.width - BUBBLE_INSET, rect.size.height - BUBBLE_INSET, rect.size.width - c, rect.size.height - BUBBLE_INSET, BUBBLE_CORNER_RADIUS); 
CGContextAddLineToPoint(ctx, c, rect.size.height - BUBBLE_INSET); 
CGContextAddArcToPoint(ctx, BUBBLE_INSET, rect.size.height - BUBBLE_INSET, BUBBLE_INSET, rect.size.height - c, BUBBLE_CORNER_RADIUS); 

CGContextClosePath(ctx); 

CGContextClip(ctx); 

CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB(); 
NSArray *colors = [NSArray arrayWithObjects:color1, color2, nil]; 

CGGradientRef gradient = CGGradientCreateWithColors(space, (CFArrayRef)colors, NULL); 
CGColorSpaceRelease(space); 

CGPoint p1 = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect)); 
CGPoint p2 = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect)); 

CGContextDrawLinearGradient(ctx, gradient, p1, p2, 0); 
CGGradientRelease(gradient);

该代码绘制一个空的白色矩形。路径建立正确（我试着调用CGContextFillPath()，结果很好地用纯色填充），color1和color2值是正确的（在调试器中看到）。这段代码有什么问题？

来源

2011-09-04 Sergey Mikhanov

你确定，color1和color2是在RGB-Space中定义的。即[[UIColor blackColor] CGColor]返回单色间隔颜色。 – vikingosegundo

原来，color1和color2是UIColor类型，这是完全错误的。在需要的地方添加'CGColor'调用，现在正在工作 –

这可能会让人感到困惑。 – vikingosegundo

原来颜色1和颜色2是UIColor类型，这是完全错误的。改了行

NSArray *colors = [NSArray arrayWithObjects:color1, color2, nil];

到

NSArray *colors = [NSArray arrayWithObjects:[color1 CGColor], [color2 CGColor], nil];

，并得到了结果，我期待。

来源

2011-09-05 23:30:45

我不确定你的颜色是如何包裹颜色数组的。

使用

CGGradientCreateWithColorComponents(rgbColorspace, components, locations, num_locations);

，而不是尝试。

CGContextRef ctx = UIGraphicsGetCurrentContext(); 
CGContextClearRect(ctx, rect); 

CGFloat c = BUBBLE_INSET + BUBBLE_CORNER_RADIUS; 

CGContextMoveToPoint(ctx, BUBBLE_INSET, c); 

CGContextAddArcToPoint(ctx, BUBBLE_INSET, BUBBLE_INSET, c, BUBBLE_INSET, BUBBLE_CORNER_RADIUS);  
CGContextAddLineToPoint(ctx, rect.size.width - c, BUBBLE_INSET); 
CGContextAddArcToPoint(ctx, rect.size.width - BUBBLE_INSET, BUBBLE_INSET, rect.size.width - BUBBLE_INSET, c, BUBBLE_CORNER_RADIUS); 
CGContextAddLineToPoint(ctx, rect.size.width - BUBBLE_INSET, rect.size.height - c); 
CGContextAddArcToPoint(ctx, rect.size.width - BUBBLE_INSET, rect.size.height - BUBBLE_INSET, rect.size.width - c, rect.size.height - BUBBLE_INSET, BUBBLE_CORNER_RADIUS); 
CGContextAddLineToPoint(ctx, c, rect.size.height - BUBBLE_INSET); 
CGContextAddArcToPoint(ctx, BUBBLE_INSET, rect.size.height - BUBBLE_INSET, BUBBLE_INSET, rect.size.height - c, BUBBLE_CORNER_RADIUS); 

CGContextClosePath(ctx); 

CGContextClip(ctx); 

CGGradientRef gradient; 
CGColorSpaceRef rgbColorspace; 
size_t num_locations = 2; 
CGFloat locations[2] = { 0.0, 1.0 }; 
CGFloat components[8] = { 1.0, 0.0, 0.0, 1.0, // Start color 
    1.0, 1.0, 1.0, 0.65 }; // End color 

rgbColorspace = CGColorSpaceCreateDeviceRGB(); 
gradient = CGGradientCreateWithColorComponents(rgbColorspace, components, locations, num_locations); 

CGPoint p1 = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect)); 
CGPoint p2 = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect)); 

CGContextDrawLinearGradient(ctx, gradient, p1, p2, 0); 
CGGradientRelease(gradient);

你会得到这样的：

偏差为5.0 半径为10.0

enter image description here

来源

2011-09-04 18:12:30

石英：无法创建带渐变填充的圆角矩形

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