我想使用几个 CALayer 作为 UIViewController 的子层。第一个是背景。
其他人都在这个背景面前。
我如何将带有孔/透明点的图像放在一起/绘制图像并将其绘制在 CALayer 中,以便背景仍然可见。
我不想为每个图像使用一个 CALayer,我最终会得到 20 000 个 CALayer 或更多......
那么如何将图像的“图像”放在 CALayer 中?(然后用作子层)
代码示例:
// rootView which is a UIViewController
- (void)viewDidLoad
{
[super viewDidLoad];
_sproutLayer = [[CGSproutLayer alloc] initWithLayer:[CALayer layer]];
[self.view.layer addSublayer:_sproutLayer];
[_sproutLayer setZPosition:1];
[_sproutLayer setNeedsDisplay];
_backgroundLayer = [[CALayer alloc] init];
CGRect positionOne = CGRectMake(100, 100, 150, 150);
_backgroundLayer.frame = positionOne;
_backgroundLayer.backgroundColor = [UIColor blueColor].CGColor;
_backgroundLayer.name = @"One";
_backgroundLayer.contents = (id) [UIImage imageNamed:@"background.png"].CGImage;
[self.view.layer addSublayer:_backgroundLayer];
[_backgroundLayer setZPosition:0];
[_backgroundLayer setNeedsDisplay];
_refreshTimer = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(doIterate:) userInfo:nil repeats:YES];
}
- (void)doIterate:(NSTimer *)timer
{
[self.something doComputeStuff];
...
[_sproutLayer draw];
}
// CGSproutLayer which is a CALAyer
- (void)draw
{
int cellSize = self.bounds.size.width / WIDTH;
double xOffset = 0;
CGRect cellFrame = CGRectMake(0, 0, cellSize, cellSize);
NSUInteger cellIndex = 0;
cellFrame.origin.x = xOffset;
for (int i = 0; i < WIDTH; i++)
{
cellFrame.origin.y = 0;
for (int j = 0; j < HEIGHT; j++, cellIndex++)
{
NSNumber *currentCell = [self.levelState.board objectAtIndex:cellIndex];
if (currentCell.intValue == sprouts)
{
[image1 drawInRect:cellFrame];
}
else if (currentCell.intValue == grass)
{
[image2 drawInRect:cellFrame];
}
cellFrame.origin.y += cellSize;
}
cellFrame.origin.x += cellSize;
}
}