大佬教程收集整理的这篇文章主要介绍了macos – NSImage和视网膜显示混乱，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。
-(NSSizE)convertPixelSizeToPointSize:(NSSizE)px { CGFloat displayScale = [[NSScreen mainScreen] BACkingScaleFactor]; NSSize res; res.width = px.width / displayScale; res.height = px.height / displayScale; return res; } -(void)awakeFromNib { CGFloat scale = [[NSScreen mainScreen] BACkingScaleFactor]; NSLog(@"BACkingScaleFactor : %f",scalE); NSImage *img = [[[NSImage alloc]initWithContentsOfFile:@"/Users/support/Pictures/cat.JPG"] autorelease]; NSBitmapImageRep *imgRep = [NSBitmapImageRep imageRepWithData:[img TIFFRepresentation]]; NSSize imgPixelSize = NsmakeSize([imgRep pixelsWide],[imgRep pixelsHigh]); NSSize imgPointSize = [self convertPixelSizeToPointSize:imgPixelSize]; [img setSize:imgPointSize]; NSLog(@"imgPixelSize.width: %f,imgPixelSize.height:%f",imgPixelSize.width,imgPixelSize.height); NSLog(@"imgPointSize.width: %f,imgPointSize.height:%f",imgPointSize.width,imgPointSize.height); [img lockFocus]; NSAffineTransform *trans = [[[NSAffineTransform alloc] init] autorelease]; [trans scaleBy:1.0 / scale]; [trans set]; NSBezierPath *path = [NSBezierPath bezierPath]; [[NSColor redColor] setStroke]; [path moveToPoint:NsmakePoint(0.0,0.0)]; [path lineToPoint:NsmakePoint(imgPixelSize.width,imgPixelSize.height)]; [path moveToPoint:NsmakePoint(0.0,imgPixelSize.height)]; [path lineToPoint:NsmakePoint(imgPixelSize.width,0.0)]; [path setLineWidth:1]; [path stroke]; [img unlockFocus]; [imageView setImage:img]; imgRep = [NSBitmapImageRep imageRepWithData:[img TIFFRepresentation]]; NSData *imageData = [imgRep representationUsingType:NSJPEGFileType properties:nil]; [imageData writeToFile:@"/Users/support/Pictures/11-5.JPG" atomically:NO]; }
在非视网膜显示器上,结果是：
和控制台显示：
2012-07-06 00:53:09.889 ReTinaTest[8074:403] BACkingScaleFactor : 1.000000 2012-07-06 00:53:09.901 ReTinaTest[8074:403] imgPixelSize.width: 515.000000,imgPixelSize.height:600.000000 2012-07-06 00:53:09.902 ReTinaTest[8074:403] imgPointSize.width: 515.000000,imgPointSize.height:600.000000
但在视网膜显示器上(我没有使用真正的视网膜显示器而是hidpi模式)：
安慰：
2012-07-06 00:56:05.071 ReTinaTest[8113:403] BACkingScaleFactor : 2.000000 2012-07-06 00:56:05.083 ReTinaTest[8113:403] imgPixelSize.width: 515.000000,imgPixelSize.height:600.000000 2012-07-06 00:56:05.084 ReTinaTest[8113:403] imgPointSize.width: 257.500000,imgPointSize.height:300.000000
如果我省略这些行：
NSAffineTransform *trans = [[[NSAffineTransform alloc] init] autorelease];
[trans scaleBy:1.0 / scale];
[trans set];
但是,如果我将[NSAffineTransform scaleBy]更改为1.0,结果是正确的
NSAffineTransform *trans = [[[NSAffineTransform alloc] init] autorelease];
[trans scaleBy:1.0];
[trans set];
安慰：
2012-07-06 01:01:03.420 ReTinaTest[8126:403] BACkingScaleFactor : 2.000000 2012-07-06 01:01:03.431 ReTinaTest[8126:403] imgPixelSize.width: 515.000000,imgPixelSize.height:600.000000 2012-07-06 01:01:03.432 ReTinaTest[8126:403] imgPointSize.width: 257.500000,imgPointSize.height:300.000000
请问有人可以解释一下吗？隐藏模式是否与视网膜显示不同？
NSAffineTransform *trans = [[[NSAffineTransform alloc] init] autorelease]; [trans set];
我不知道它是否是一个错误,或者它的工作方式.
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