CATiledLayer问题

Question

我想在PhotoScroller应用程序中使用CATiledLayer。 在我TilingView.m我有

+ (Class)layerClass { 
    return [CATiledLayer class]; 
} 

- (id)initWithImageName:(NSString *)name size:(CGSize)size 
{ 
    if ((self = [super initWithFrame:CGRectMake(0, 0, size.width, size.height)])) { 
     imageName = [name retain]; 

     CATiledLayer *tiledLayer = (CATiledLayer *)[self layer]; 
     tiledLayer.levelsOfDetail = 4; 
    } 
    return self; 
} 

- (void)drawRect:(CGRect)rect { 
    CGContextRef context = UIGraphicsGetCurrentContext(); 

    // get the scale from the context by getting the current transform matrix, then asking for 
    // its "a" component, which is one of the two scale components. We could also ask for "d". 
    // This assumes (safely) that the view is being scaled equally in both dimensions. 
    CGFloat scale = CGContextGetCTM(context).a; 

    CATiledLayer *tiledLayer = (CATiledLayer *)[self layer]; 
    CGSize tileSize = tiledLayer.tileSize; 

    if (scale != 0.125) 
    { 
     UIImage *image = [UIImage imageNamed:imageName]; 
     CGRect rect = self.bounds; 
     [image drawInRect:rect]; 
     return; 
    } 

    // Even at scales lower than 100%, we are drawing into a rect in the coordinate system of the full 
    // image. One tile at 50% covers the width (in original image coordinates) of two tiles at 100%. 
    // So at 50% we need to stretch our tiles to double the width and height; at 25% we need to stretch 
    // them to quadruple the width and height; and so on. 
    // (Note that this means that we are drawing very blurry images as the scale gets low. At 12.5%, 
    // our lowest scale, we are stretching about 6 small tiles to fill the entire original image area. 
    // But this is okay, because the big blurry image we're drawing here will be scaled way down before 
    // it is displayed.) 
    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(rect)/tileSize.width); 
    int lastCol = floorf((CGRectGetMaxX(rect)-1)/tileSize.width); 
    int firstRow = floorf(CGRectGetMinY(rect)/tileSize.height); 
    int lastRow = floorf((CGRectGetMaxY(rect)-1)/tileSize.height); 

    for (int row = firstRow; row <= lastRow; row++) { 
     for (int col = firstCol; col <= lastCol; col++) { 
      UIImage *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]; 

      if (self.annotates) { 
       [[UIColor whiteColor] set]; 
       CGContextSetLineWidth(context, 6.0/scale); 
       CGContextStrokeRect(context, tileRect); 
      } 
     } 
    } 
} 

所以，当我使用Retina显示屏，它总是进入

if (scale != 0.125) 
    { 
     UIImage *image = [UIImage imageNamed:imageName]; 
     CGRect rect = self.bounds; 
     [image drawInRect:rect]; 
     return; 
    } 

它可以完美运行在模拟器（视网膜显示），但在设备上它抛出异常（图片！=零，我已经检查）

[image drawInRect:rect]; 

例外

0x35affc70: push {r4, r5, r6, r7, lr} 
0x35affc72: add r7, sp, #12 
0x35affc74: push.w {r8, r10, r11} 
0x35affc78: ldr r1, [r0] 
0x35affc7a: ldr r2, [r0, #12] 
0x35affc7c: cmp.w r2, r1, lsl #2 
0x35affc80: blo 0x35affd06    ; ImageIO_ABGR_TO_ARGB_8Bit + 150 
0x35affc82: ldr r3, [r0, #24] 
0x35affc84: lsls r2, r1, #2 
0x35affc86: cmp r3, r2 
0x35affc88: blo 0x35affd06    ; ImageIO_ABGR_TO_ARGB_8Bit + 150 
0x35affc8a: ldr r2, [r0, #4] 
0x35affc8c: cmp r2, #0 
0x35affc8e: beq 0x35affd06    ; ImageIO_ABGR_TO_ARGB_8Bit + 150 
0x35affc90: bic lr, r1, #7 
0x35affc94: ldr r3, [r0, #8] 
0x35affc96: ldr.w r12, [r0, #20] 
0x35affc9a: sub.w r4, r1, lr 
0x35affc9e: asrs r5, r1, #3 
0x35affca0: mov r6, r12 
0x35affca2: mov r8, r3 
0x35affca4: cbz r5, 0x35affcbe   ; ImageIO_ABGR_TO_ARGB_8Bit + 78 
0x35affca6: mov r8, r3 
0x35affca8: mov r9, r5 
0x35affcaa: mov r6, r12 
0x35affcac: vld4.8 {d0, d1, d2, d3}, [r8]! 
0x35affcb0: vswp d0, d2 
0x35affcb4: vst4.8 {d0, d1, d2, d3}, [r6]!  ;!!!!!!!!string with exception!!!!!!!!!!!! 
0x35affcb8: subs.w r9, r9, #1 
0x35affcbc: bne 0x35affeac    ; slab_dealloc + 132 
0x35affcbe: cmp lr, r1 
0x35affcc0: bge 0x35affcf8    ; ImageIO_ABGR_TO_ARGB_8Bit + 136 
0x35affcc2: add.w r8, r8, #2 
0x35affcc6: adds r6, #2 
0x35affcc8: mov r9, r4 
0x35affcca: ldrb.w r11, [r8] 
0x35affcce: subs.w r9, r9, #1 
0x35affcd2: ldrb r10, [r8, #-2] 
0x35affcd6: strb r11, [r6, #-2] 
0x35affcda: ldrb r11, [r8, #-1] 
0x35affcde: strb r11, [r6, #-1] 
0x35affce2: strb.w r10, [r6] 
0x35affce6: ldrb.w r10, [r8, #1] 
0x35affcea: add.w r8, r8, #4 
0x35affcee: strb.w r10, [r6, #1] 
0x35affcf2: add.w r6, r6, #4 
0x35affcf6: bne 0x35affeca    ; current_timestamp + 26 
0x35affcf8: ldr r6, [r0, #12] 
0x35affcfa: subs r2, #1 
0x35affcfc: ldr.w r8, [r0, #24] 
0x35affd00: add r3, r6 
0x35affd02: add r12, r8 
0x35affd04: bne 0x35affea0    ; slab_dealloc + 120 
0x35affd06: pop.w {r8, r10, r11} 
0x35affd0a: pop {r4, r5, r6, r7, pc} 

预先感谢您。

Answer 1

问题是在不好的形象（我转换图像从JPG到PNG与在线转换器和面临困难，比我用Photoshop并且都变好了）

Answer 2

你已经检查过fileName了吗？

在代码中搜索错误之前，请检查图像的文件名：记住模拟器不区分大小写（FileName.png == filename.png - >它会被加载）但iDevice是大小写的，敏感（FileName.png！=文件名.png - >它不会被加载）