我正在开发具有某些游戏领域的游戏,该游戏是在某些视图中绘制的。我的游戏场总是相对于他的中心绘制,所以我只是简单的捏
- (void)pinch:(UIPinchGestureRecognizer *)gesture
{
if ((gesture.state == UIGestureRecognizerStateChanged) ||
(gesture.state == UIGestureRecognizerStateEnded)) {
self.gameBoardGridView.scale *= gesture.scale; // adjust our scale
gesture.scale = 1;
}
和泛
-(void)pan:(UIPanGestureRecognizer *)recognizer
{
CGPoint translatedPoint = [recognizer translationInView:self.gameBoardGridView];
self.gameBoardGridView.gridCenter = CGPointMake(self.gameBoardGridView.gridCenter.x + translatedPoint.x, self.gameBoardGridView.gridCenter.y + translatedPoint.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.gameBoardGridView];
}
但我需要其他类型的缩放。当您放下两根手指然后移动其中一根时,该区域会按应有的方式扩展(放大),但手指下方的像素不再位于手指下方。图像从图像的中心缩放,而不是两个手指之间的中点。
我尝试了很多示例,但没有像我想要的那样工作。最后我写了这个,它几乎是正确的,但不完全
- (void)pinch:(UIPinchGestureRecognizer *)gesture
{
CGFloat curScale = gesture.scale;
static CGPoint startPoint;
if (gesture.state == UIGestureRecognizerStateBegan) {
startPoint = [gesture locationInView:self.gameBoardGridView];
}
if ((gesture.state == UIGestureRecognizerStateChanged) ||
(gesture.state == UIGestureRecognizerStateEnded)) {
self.gameBoardGridView.scale *= gesture.scale;
CGFloat widthDelta = self.gameBoardGridView.gridWidth * fabs(gesture.scale - 1) / 3;
CGFloat heightDelta = self.gameBoardGridView.gridHeight * fabs(gesture.scale - 1) / 3;
gesture.scale = 1;
CGPoint lastPoint = self.gameBoardGridView.gridCenter;
const CGFloat epsilon = 5;
CGFloat coef = 1.0;
if(curScale < 1) {
coef = -1.0;
}
if (startPoint.x + epsilon < self.view.frame.size.width / 2) {
lastPoint.x += widthDelta*coef;
}
else if (startPoint.x - epsilon > self.view.frame.size.width / 2) {
lastPoint.x -= widthDelta*coef;
}
if (startPoint.y + epsilon < self.view.frame.size.height / 2) {
lastPoint.y += heightDelta*coef;
}
else if (startPoint.y - epsilon > self.view.frame.size.height / 2) {
lastPoint.y -= heightDelta*coef;
}
self.gameBoardGridView.gridCenter = lastPoint;
}
}
可能还有其他方法可以做到这一点?