我正在 iOS 中创建一个旋钮按钮。图形设计师给了我 png 图层，所以我使用图像上下文来允许图层的混合。
在旋转时，只有一些图层被旋转。我的目标是为这些旋转设置动画。
目前，我正在使用
- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
- (BOOL)continueTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
- (BOOL)endTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
在这些方法中，我计算图像所需的旋转并绘制它。
这工作正常。我遇到的障碍是
- (BOOL)endTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
我想做一个“捕捉”动画。我怎样才能做到这一点？由于混合，我不确定在这种情况下如何使用仿射变换。以下方法是我构建图像的方式：
- (UIImage *)knobImageWithRadians:(float)radians
{
UIImage *i05 = [UIImage imageNamed:@"05 - Metal Over Empty Space - ROTATE ME.png"];
UIImage *i04 = [UIImage imageNamed:@"04 - Inner Knob.png"];
UIImage *i03 = [UIImage imageNamed:@"03 - Over Knob Metal - (OVERLAY BLEND) - ROTATE ME.png"];
UIImage *i02 = [UIImage imageNamed:@"02 - Numbers and Dashes - ROTATE ME.png"];
UIImage *i01 = [UIImage imageNamed:@"01 - Reflective Overlay - (COLOR DODGE BLEND).png"];
CGSize size = i11.size;
UIGraphicsBeginImageContext(size);
CGContextRef bitmap = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(bitmap, size.width/2, size.height/2);
[i04 drawInRect:CGRectMake(-i04.size.width/2, -i04.size.height/2, i04.size.width, i04.size.height) blendMode:kCGBlendModeNormal alpha:1.0];
CGContextRotateCTM(bitmap, radians);
[i03 drawInRect:CGRectMake(-i03.size.width/2, -i03.size.height/2, i03.size.width, i03.size.height) blendMode:kCGBlendModeOverlay alpha:1.0];
[i02 drawInRect:CGRectMake(-i02.size.width/2, -i02.size.height/2, i02.size.width, i02.size.height) blendMode:kCGBlendModeNormal alpha:1.0];
CGContextRotateCTM(bitmap, -radians);
[i01 drawInRect:CGRectMake(-i01.size.width/2, -i01.size.height/2, i01.size.width, i01.size.height) blendMode:kCGBlendModeColorDodge alpha:1.0];
UIImage* blendedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return blendedImage;
}
更新：
现在，我只是让它直接拍摄，没有任何动画。