objective-c 截屏

调用的时候直接把需要裁剪的view的layer传进去就可以了


- (UIImage *)imageFromLayer:(CALayer *)layer
{
UIImage *outputImage = nil;
CGSize layerSize;

layerSize = layer.frame.size;
if( layerSize.width <= 0 ||
   layerSize.height <= 0 )
{
return nil;
}
if( layer )
{
CGImageRef workImage = NULL;
static CGColorSpaceRef s_ColorSpace = NULL;
CGContextRef bitmapContext = NULL;

if (!s_ColorSpace) {
s_ColorSpace = CGColorSpaceCreateDeviceRGB();
}
if (!bitmapContext) {
bitmapContext = CGBitmapContextCreate(NULL, layerSize.width, layerSize.height, 8, 0, s_ColorSpace, kCGImageAlphaNoneSkipLast);
CGContextTranslateCTM(bitmapContext, 0.0f, layerSize.height);
CGContextScaleCTM(bitmapContext, 1.0f, -1.0f);
CGContextSetInterpolationQuality(bitmapContext, kCGInterpolationNone);
CGContextSetShouldAntialias(bitmapContext, NO);
CGContextSetAllowsAntialiasing(bitmapContext, NO);
}

[layer renderInContext:bitmapContext];
workImage = CGBitmapContextCreateImage(bitmapContext);
if (workImage) {
outputImage = [UIImage imageWithCGImage:workImage];
CGImageRelease(workImage);
}
if (bitmapContext) {
CGContextRelease(bitmapContext);
}
}
return outputImage;
}