objective-c – OS X上的CATiledLayers

>我需要能够缩放(在鼠标中心)和平移
>图像不应改变其宽度：高度比(不应调整大小,仅缩放).
>这应该在Mac OS 10.9上运行(不是iOS！)
>内存使用量不应该很大(尽管最高可达100 MB).

我有必要的图像在一个文件中完成,并且还平铺成许多(甚至有不同的缩放级别).我更喜欢使用瓷砖,因为内存应该更容易,但两种选择都可用.

大多数在线示例都是指iOS,因此使用UIScrollView进行缩放/平移,但我无法复制NSScrollView的行为.我发现Mac OS X的唯一例子是this,但他的缩放始终是左下角,而不是中间,当我调整代码使用png文件而不是pdf时,内存使用大约400 MB …

到目前为止,这是我最好的尝试：

@implementation MyView{
    CATiledLayer *tiledLayer;
}
-(void)awakeFromNib{
    NSLog(@"Es geht los");
    tiledLayer = [CATiledLayer layer];

    // set up this view & its layer
    self.wantsLayer = YES;
    self.layer = [CALayer layer];
    self.layer.masksToBounds = YES;
    self.layer.backgroundColor = CGColorGetConstantColor(kCGColorWhite);

    // set up the tiled layer
    tiledLayer.delegate = self;
    tiledLayer.levelsOfDetail = 4;
    tiledLayer.levelsOfDetailBias = 5;
    tiledLayer.anchorPoint = CGPointZero;
    tiledLayer.bounds = CGRectMake(0.0f,0.0f,41*256,22*256);
    tiledLayer.autoresizingMask = kCALayerNotSizable;
    tiledLayer.tileSize = CGSizeMake(256,256);
    self.frame = CGRectMake(0.0f,22*256);
    self.layer = tiledLayer;
    //[self.layer addSublayer:tiledLayer];
    [tiledLayer setNeedsDisplay];

}

-(void)drawRect:(NSRect)dirtyRect{
    CGContextRef context = [[NSGraphicsContext currentContext] graphicsPort];


    CGFloat scale = CGContextGetCTM(context).a;

    CGSize tileSize = tiledLayer.tileSize;


    tileSize.width /= scale;
    tileSize.height /= scale;

    // calculate the rows and columns of tiles that intersect the rect we have been asked to draw
    int firstCol = floorf(CGRectGetMinX(dirtyRect) / tileSize.width);
    int lastCol = floorf((CGRectGetMaxX(dirtyRect)-1) / tileSize.width);
    int firstRow = floorf(CGRectGetMinY(dirtyRect) / tileSize.height);
    int lastRow = floorf((CGRectGetMaxY(dirtyRect)-1) / tileSize.height);

    for (int row = firstRow; row <= lastRow; row++) {
        for (int col = firstCol; col <= lastCol; col++) {
            NSImage *tile = [self tileForScale:scale row:row col:col];
            CGRect tileRect = CGRectMake(tileSize.width * col,tileSize.height * row,tileSize.width,tileSize.height);

            // if the tile would stick outside of our bounds,we need to truncate it so as
            // to avoid stretching out the partial tiles at the right and bottom edges
            tileRect = CGRectIntersection(self.bounds,tileRect);

            [tile drawInRect:tileRect];
        }
    }
}

-(BOOL)isFlipped{
    return YES;
}

但这会使图像变形,并且不能正确缩放或平移(但至少瓷砖选择有效)……

我不敢相信这很难,任何帮助都会非常感激.谢谢 ：)