私はUIImageに丸いコーナーを追加するために次のコードを使用していますが、丸みを帯びたコーナーが透明または "透明"の代わりに "白い"領域を表示しています。私はここで間違って何をやっている:透明な丸いコーナーを持つUIImage
- (UIImage *)makeRoundCornerImageWithCornerWidth:(int)cornerWidth cornerHeight:(int)cornerHeight {
UIImage * newImage = nil;
if (self != nil) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int w = self.size.width;
int h = self.size.height;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 * w, colorSpace, kCGImageAlphaPremultipliedFirst);
CGContextBeginPath(context);
CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
[self addRoundedRectToPath:context rect:rect width:cornerWidth height:cornerHeight];
CGContextClosePath(context);
CGContextClip(context);
CGContextDrawImage(context, CGRectMake(0, 0, w, h), self.CGImage);
CGImageRef imageMasked = CGBitmapContextCreateImage(context);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
newImage = [[UIImage imageWithCGImage:imageMasked] retain];
CGImageRelease(imageMasked);
[pool release];
}
return [newImage autorelease];
}
- (void)addRoundedRectToPath:(CGContextRef)context rect:(CGRect)rect width:(float)ovalWidth height:(float)ovalHeight {
float fw, fh;
// If the width or height of the corner oval is zero, then it reduces to a right angle,
// so instead of a rounded rectangle we have an ordinary one.
if (ovalWidth == 0 || ovalHeight == 0) {
CGContextAddRect(context, rect);
return;
}
// Save the context's state so that the translate and scale can be undone with a call
// to CGContextRestoreGState.
CGContextSaveGState(context);
// Translate the origin of the contex to the lower left corner of the rectangle.
CGContextTranslateCTM (context, CGRectGetMinX(rect), CGRectGetMinY(rect));
//Normalize the scale of the context so that the width and height of the arcs are 1.0
CGContextScaleCTM (context, ovalWidth, ovalHeight);
// Calculate the width and height of the rectangle in the new coordinate system.
fw = CGRectGetWidth (rect)/ovalWidth;
fh = CGRectGetHeight (rect)/ovalHeight;
// CGContextAddArcToPoint adds an arc of a circle to the context's path (creating the rounded
// corners). It also adds a line from the path's last point to the begining of the arc, making
// the sides of the rectangle.
CGContextMoveToPoint(context, fw, fh/2); // Start at lower right corner
CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1); // Top right corner
CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1); // Top left corner
CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1); // Lower left corner
CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1); // Back to lower right
// Close the path
CGContextClosePath(context);
// Restore the context's state. This removes the translation and scaling
// but leaves the path, since the path is not part of the graphics state.
CGContextRestoreGState(context);
}
のための仕事のように聞こえる...それは丸みを帯びた角を示す必要があります。.. – lukya
これはコードで読むことができる素晴らしい投稿です - http://vocaro.com/trevor/blog/2009/10/12/resize-a-uiimage-the-right-way/ – petert
@lukya、はい、できますと私は持っているが、私はちょうどこのコードの問題をチェックしたいと思った。 – Mustafa