CoreGraphics/石英阴影

发布于 2024-10-16 18:45:49 字数 783 浏览 3 评论 0原文

我目前正在 iPhone 上使用 CoreGraphics/Quartz CGContextAddLineToPoint 函数绘制正弦曲线：

CGContextRef _context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(_context, 6.0);
CGColorSpaceRef _colorSpace = CGColorSpaceCreateDeviceRGB(); 
CGFloat _whiteColorComponents[] = {1.0, 1.0, 1.0, 1.0};
CGColorRef _color = CGColorCreate(_colorSpace, _whiteColorComponents);
CGContextSetStrokeColorWithColor(_context, _color);

CGContextMoveToPoint(_context, 0, 200);

float _increment = 1;
for (float _i = 0; _i<320; _i=_i+_increment) {
    float _sin = ((sin(_i/10) + 1) * 100) + 100;
    CGContextAddLineToPoint(_context, _i, _sin);
}

CGContextStrokePath(_context);

现在我想向整个路径添加阴影（而不是外发光）。使用 Quartz 是否可以实现这一点（只阅读有关 CGShading 的内容，但这似乎有点困难）？

先感谢您，亚历山大

原文

I'm currently drawing a sinus-curve using the CoreGraphics/Quartz CGContextAddLineToPoint-function on the iPhone:

CGContextRef _context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(_context, 6.0);
CGColorSpaceRef _colorSpace = CGColorSpaceCreateDeviceRGB(); 
CGFloat _whiteColorComponents[] = {1.0, 1.0, 1.0, 1.0};
CGColorRef _color = CGColorCreate(_colorSpace, _whiteColorComponents);
CGContextSetStrokeColorWithColor(_context, _color);

CGContextMoveToPoint(_context, 0, 200);

float _increment = 1;
for (float _i = 0; _i<320; _i=_i+_increment) {
    float _sin = ((sin(_i/10) + 1) * 100) + 100;
    CGContextAddLineToPoint(_context, _i, _sin);
}

CGContextStrokePath(_context);

Now I would like to add a shadow (rather an outer-glow) to the whole path. Is this possible using Quartz (only read something about CGShading, but this seems kind of difficult)?

Thank you in advance,
Alexander

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