Question

我正在将Cocoa-Java代码迁移到Cocoa + JNI，因为Cocoa-Java已被弃用。代码打印存储在文件中的图像。新的Cocoa代码基本上是：

NSImage *image = [[NSImage alloc] initWithContentsOfFile:spoolFile];
if ( [image isValid] ) {
    NSImageView *view = [[NSImageView alloc] init];
    [view setImage:image];
    [view setImageScaling:NSScaleProportionally];

    NSPoint p;
    NSSize s;

    p.x = static_cast<float>( boundsX );
    p.y = static_cast<float>( boundsY );
    [view setBoundsOrigin:p];

    s.width  = static_cast<float>( boundsWidth );
    s.height = static_cast<float>( boundsHeight );
    [view setBoundsSize:s];

    NSPrintInfo *info = [NSPrintInfo sharedPrintInfo];
    [info setHorizontalPagination:NSClipPagination];
    [info setVerticalPagination:NSClipPagination];
    [info setHorizontallyCentered:NO];
    [info setVerticallyCentered:NO];

    p.x = static_cast<float>( boundsX );
    p.y = static_cast<float>( [info paperSize].height - boundsHeight - boundsY );
    [view translateOriginToPoint:p];

    NSPrintOperation *printOp =
        [NSPrintOperation printOperationWithView:view printInfo:info];
    [printOp setShowsPrintPanel:NO];
    [printOp runOperation];
}

运行此代码最终会崩溃：

Thread 0 Crashed:
0   com.apple.AppKit   0x9484ac75 -[NSConcretePrintOperation(NSInternal) _tryToSetCurrentPageNumber:] + 345
1   com.apple.AppKit   0x948d88cf -[NSView(NSPrintingInternal) _printForCurrentOperation] + 524
2   com.apple.AppKit   0x948d85c5 -[NSConcretePrintOperation _renderView] + 358
3   com.apple.AppKit   0x9491f0c0 -[NSConcretePrintOperation runOperation] + 362

为什么呢？如何只打印存储在文件中的图像？

Answer 1

NSImageView *view = [[NSImageView alloc] init];

那是无效的。您需要使用initWithFrame:初始化视图。您可能希望传递一个由NSZeroPoint和图像大小组成的帧。

关于setBoundsOrigin:和setBoundsSize:的使用：我不确定这些是否可行，假设您要裁剪图像。您可以尝试它们（在解决上述问题之后），但我觉得从旧版本的所需部分创建新图像会更安全。您可以通过创建所需大小的空图像，锁定焦点，在新图像的原点绘制旧图像的正确部分，并将焦点解锁到新图像，然后给出新图像而不是旧的到图像视图。

Answer 2

~~这是第二次分配给p.y时的拼写错误吗？它看起来不像你定义info直到2行......~~

此外，通过传递ints而不是手动构建它们并使用static_cast<float>来使用NSMakePoint()和NSMakeSize()会不会更简单？这似乎是一种非常C ++的方法......

例如，这样的事情可以起作用吗？

NSImage *image = [[NSImage alloc] initWithContentsOfFile:spoolFile];
if ([image isValid]) {
    NSPrintInfo *info = [NSPrintInfo sharedPrintInfo];
    [info setHorizontalPagination:NSClipPagination];
    [info setVerticalPagination:NSClipPagination];
    [info setHorizontallyCentered:NO];
    [info setVerticallyCentered:NO];

    NSImageView *view = [[NSImageView alloc] init];
    [view setImage:image];
    [view setImageScaling:NSScaleProportionally];
    [view setBoundsOrigin:NSMakePoint(boundsX, boundsY)];
    [view setBoundsSize:NSMakeSize(boundsWidth, boundsHeight)];
    [view translateOriginToPoint:NSMakePoint(boundsX, [info paperSize].height -
                                                      boundsHeight - boundsY)];

    NSPrintOperation *printOp = [NSPrintOperation printOperationWithView:view printInfo:info];
    [printOp setShowsPrintPanel:NO];
    [printOp runOperation];
}

打印NSImage

2 个答案: