Objective c iOS打印接口导致自定义视图出现转换问题

我现在在iOS的打印界面上挣扎了很长一段时间。我所拥有的是一个视图控制器，它具有一个自定义UIView，可以在drawRect中进行绘制：

以下是该图纸在iPad上的外观示例（包括一些彩色测试线）：

我已经设置了一个UIPrintRenderer子类，用于打印页眉和页脚，并为自定义UIView的drawRect:方法提供content rect drawContentForPageAtIndex:inRect:。调试器告诉我，drawRect:总是被调用的-无论renderer类中是否存在rect drawContentForPageAtIndex:inRect:都没有关系。因此，我不使用rect-drawContentForPageAtIndex:inRect:进行绘制，而是使用drawRect:进行绘制

当打印机模拟器提供A4纸张格式时，我得到的纸张rect为[0,0841.89595.276]，可打印rect为[11.9905,11.9906817.909571.294]，内容rect为[11.9905,33.9906817.909530.294]。我确实不明白的是，drawRect:从打印接口获取[0,069530.294]的rect。这是内容矩形的高度，但宽度是在正常绘制时与矩形的距离，不打印：[0,0,695,648]。在模拟器输出页面中看起来是这样的（当然也添加了一些测试帧、线和圆）：

下面是一些代码，首先是视图控制器中设置打印的部分：

- (IBAction)pressedPrint:(id)sender
{
    UIPrintInteractionController*   printCtrl = [UIPrintInteractionController sharedPrintController];
    UIPrintInfo*                    printInfo = [UIPrintInfo printInfo];

    NSLog(@"%s prepare printing parameters etc.", __func__);
    printCtrl.delegate       = self;
    printInfo.outputType     = UIPrintInfoOutputPhoto;
    printInfo.orientation    = UIPrintInfoOrientationLandscape;
    printInfo.jobName        = [NSString stringWithFormat:@"%@ - %@", NSLocalizedString(@"NavTitleMain", @""), self.title];
    printInfo.duplex         = UIPrintInfoDuplexNone;
    printCtrl.printInfo      = printInfo;
    printCtrl.showsPageRange = NO;

    // This code uses a custom UIPrintPageRenderer so that it can draw a header and footer.
    DVPrintPageRenderer*    myRenderer = [[DVPrintPageRenderer alloc] init];

    // The DVPrintPageRenderer class provides a jobtitle that it will label each page with.
    myRenderer.jobTitle      = printInfo.jobName;
    myRenderer.isTwoPageView = NO;
    myRenderer.footerText    = [centralDocument sharedInstance].docTitle;
    myRenderer.drawView      = self.drawArea;

    // To draw the content of each page, a UIViewPrintFormatter is used.
    UIViewPrintFormatter*   viewFormatter = [self.drawArea viewPrintFormatter];
    UIFont*                 titleFont     = [UIFont fontWithName:@"Helvetica" size:HEADER_TEXT_HEIGHT];
    CGSize                  titleSize     = [myRenderer.jobTitle getSizeWithFont:titleFont];
    UIFont*                 footerFont    = [UIFont fontWithName:@"Helvetica" size:FOOTER_TEXT_HEIGHT];
    CGSize                  footerSize    = [myRenderer.footerText getSizeWithFont:footerFont];

    viewFormatter.startPage = 0;
    myRenderer.headerHeight = titleSize.height  + HEADER_FOOTER_MARGIN_PADDING;
    myRenderer.footerHeight = footerSize.height + HEADER_FOOTER_MARGIN_PADDING;
    [myRenderer addPrintFormatter:viewFormatter startingAtPageAtIndex:0];
    // Set our custom renderer as the printPageRenderer for the print job.
    printCtrl.printPageRenderer = myRenderer;
    drawArea.isPrinting     = YES;
    drawArea.printRenderer  = myRenderer;
    NSLog(@"%s before presenting the printer dialog", __func__);

    void (^completionHandler)(UIPrintInteractionController*, BOOL, NSError*) =
    ^(UIPrintInteractionController* printController, BOOL completed, NSError* error)
    {
        drawArea.isPrinting    = NO;
        drawArea.printRenderer = nil;

        if (!completed && error)
        {
            NSLog(@"Printing could not complete because of error: %@", error);
        }
    };

    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
    {
        [printCtrl presentFromBarButtonItem:sender animated:YES completionHandler:completionHandler];
    }
    else
    {
        [printCtrl presentAnimated:YES completionHandler:completionHandler];
    }
}

drawRect:的第一个代码部分可能也与此相关：

- (void)drawRect: (CGRect)rect
{
    // Drawing code.
    NSLog(@"%s entered for %@", __func__, (isPrinting ? @"printing" : @"screen drawing"));
    NSInteger   colorCount = (colorArray  == nil) ? -1 : [colorArray count];
    NSInteger   graphCount = (graphPoints == nil) ? -1 : [graphPoints count];

    CGContextRef    context = UIGraphicsGetCurrentContext();

    CGContextSaveGState(context);

    if (isPrinting)
    {
        // make sure that we'll print the frame rectangle
        CGRect  newRect = CGRectInset(printRenderer.rectContent, 2.0, 2.0);

        saveGraphRect = drawGraphRect;
        saveBackColor = viewBackColor;
        saveTextColor = viewBackColor;
        CGContextTranslateCTM(context, printRenderer.rectContent.origin.x, -printRenderer.rectContent.origin.y);
        NSLog(@"%s content = [%g, %g, %g, %g]", __func__,
              printRenderer.rectContent.origin.x, printRenderer.rectContent.origin.y,
              printRenderer.rectContent.size.width, printRenderer.rectContent.size.height);
        NSLog(@"%s rect(1) = [%g, %g, %g, %g]", __func__,
              rect.origin.x, rect.origin.y, rect.size.width, rect.size.height);
        rect          = CGRectMake(ceilf(newRect.origin.x),    ceilf(newRect.origin.y),
                                   floorf(newRect.size.width), floorf(newRect.size.height));
        CGContextTranslateCTM(context, rect.origin.x, rect.origin.y);
        rect.origin   = CGPointMake(0.0, 0.0);

        usedBounds    = rect;
        drawGraphRect = [self makeInsetDrawRectFrom:rect];
        viewBackColor = [UIColor whiteColor];
        axisTextColor = [UIColor blackColor];
        NSLog(@"%s prepared for printing", __func__);
        NSLog(@"%s bounds = [%g, %g, %g, %g]", __func__,
              self.bounds.origin.x, self.bounds.origin.y,
              self.bounds.size.width, self.bounds.size.height);
        NSLog(@"%s paper = [%g, %g, %g, %g]", __func__,
              printRenderer.paperRect.origin.x, printRenderer.paperRect.origin.y,
              printRenderer.paperRect.size.width, printRenderer.paperRect.size.height);
        NSLog(@"%s rect(2) = [%g, %g, %g, %g]", __func__,
              rect.origin.x, rect.origin.y, rect.size.width, rect.size.height);
        NSLog(@"%s draw = [%g, %g, %g, %g]", __func__,
              drawGraphRect.origin.x, drawGraphRect.origin.y, drawGraphRect.size.width, drawGraphRect.size.height);
    }
    else
    {
        usedBounds = self.bounds;
        ...

drawRect:中RECT的NSLog输出也与以下内容相关：

2014-01-21 17:15:39.906 iELANA[19015:a0b] -[DrawView drawRect:] entered for screen drawing
2014-01-21 17:15:39.906 iELANA[19015:a0b] -[DrawView drawRect:] bounds = [0, 0, 695, 648]
2014-01-21 17:15:39.906 iELANA[19015:a0b] -[DrawView drawRect:] rect = [0, 0, 695, 648]
2014-01-21 17:15:39.906 iELANA[19015:a0b] -[DrawView drawRect:] draw = [62, 2, 631, 584]
2014-01-21 17:15:40.645 iELANA[19015:a0b] -[viewDiagram pressedPrint:] prepare printing parameters etc.
2014-01-21 17:15:40.645 iELANA[19015:a0b] -[viewDiagram pressedPrint:] before presenting the printer dialog
2014-01-21 17:15:46.131 iELANA[19015:a0b] printableRect = [11.9905, 11.9906, 817.909, 571.294]
2014-01-21 17:15:46.131 iELANA[19015:a0b] headerRect = [11.9905, 11.9906, 817.909, 22]
2014-01-21 17:15:46.131 iELANA[19015:a0b] header text size = [297, 17]
2014-01-21 17:15:46.133 iELANA[19015:a0b] -[DVPrintPageRenderer drawContentForPageAtIndex:inRect:] page = 0, rect [11.9905, 33.9906, 817.909, 530.294]
2014-01-21 17:15:46.133 iELANA[19015:a0b] paper     rect = [0, 0, 841.89, 595.276]
2014-01-21 17:15:46.133 iELANA[19015:a0b] printable rect = [11.9905, 11.9906, 817.909, 571.294]
2014-01-21 17:15:46.133 iELANA[19015:a0b] -[DrawView drawRect:] entered for printing
2014-01-21 17:15:46.134 iELANA[19015:a0b] -[DrawView drawRect:] content = [11.9905, 33.9906, 817.909, 530.294]
2014-01-21 17:15:46.134 iELANA[19015:a0b] -[DrawView drawRect:] rect(1) = [0, 0, 695, 530.294]
2014-01-21 17:15:46.134 iELANA[19015:a0b] -[DrawView drawRect:] prepared for printing
2014-01-21 17:15:46.134 iELANA[19015:a0b] -[DrawView drawRect:] bounds = [0, 0, 695, 648]
2014-01-21 17:15:46.134 iELANA[19015:a0b] -[DrawView drawRect:] paper = [0, 0, 841.89, 595.276]
2014-01-21 17:15:46.134 iELANA[19015:a0b] -[DrawView drawRect:] rect(2) = [0, 0, 813, 526]
2014-01-21 17:15:46.135 iELANA[19015:a0b] -[DrawView drawRect:] draw = [62, 2, 749, 462]
2014-01-21 17:15:46.140 iELANA[19015:a0b] printableRect = [11.9905, 11.9906, 817.909, 571.294]
2014-01-21 17:15:46.140 iELANA[19015:a0b] footerRect = [11.9905, 564.285, 817.909, 19]
2014-01-21 17:15:46.140 iELANA[19015:a0b] footer text size = [296, 14]

绘图代码使用核心图形和UIKit绘制框架、线条等。文本输出使用核心文本。因此，应用正确的CTM变换仍有一些工作要做。但第一个主要问题是：

为什么drawRect：从打印界面获得一个奇怪的rect而不是内容rect？如果我不能打破这条规则，那么对于iPhone打印而不是iPad来说，情况会非常糟糕——在使用当前编码的iPhone上，情况看起来更糟

我是否应该在打印渲染器的drawContentForPageAtIndex:inRect:中更好地打印图形代码

非常感谢您的帮助：-）

康兰

添加：

看起来确实如此，传递给drawRect:的图形上下文不适用于打印要求。当我直接从drawRect:返回打印并将打印代码添加到drawContentForPageAtIndex:inRect:，我得到了更好的（测试）输出：

但我不明白的是，我仍然需要你的帮助的是轴文本的定位代码，它是用核心文本绘制的。我尝试过非常不同的CTM转换组合。。。但我使用的任何一种语言都会导致文本的错误定位。这就是我对x轴上的文本输出所做的：

- (void)drawAxisValueXin: (CGContextRef)context withText: (NSString*)axisValueX dockToPoint: (CGPoint)dockPoint
{
    BOOL        isRetina  = (!isPrinting && AfxGetApp().isRetina);
    CGFloat     rMul      = (isRetina) ? 2.0 : 1.0;
    CGFloat     fontSize  = 10.0;
    CTFontRef   helvetica = CTFontCreateWithName(CFSTR("Helvetica"), fontSize, NULL);

    if (isRetina)
    {
        dockPoint.x *= 2.0;
        dockPoint.y *= 2.0;
    }

    // flip the coordinate system
    CGContextSaveGState(context);

    if (isPrinting)
    {
        CGContextSetTextMatrix(context, CGAffineTransformIdentity);
        CGContextTranslateCTM(context, 0.0f, CGRectGetHeight(printRenderer.paperRect));
        CGContextScaleCTM(context, 1.0f, -1.0f);
    }
    else
    {
        CGContextSetTextMatrix(context, CGAffineTransformIdentity);
        CGContextTranslateCTM(context, 0.0f, CGRectGetHeight(usedBounds) * rMul);
        CGContextScaleCTM(context, 1.0f, -1.0f);
    }

    // make the attributed string
    NSMutableAttributedString*  attrString = [[NSMutableAttributedString alloc] initWithString:axisValueX];
    NSRange                     strRange   = NSMakeRange(0, [attrString length]);

    [attrString addAttribute: (id)kCTFontAttributeName
                       value: (__bridge id)helvetica
                       range: strRange];
    [attrString addAttribute: (id)kCTForegroundColorAttributeName
                       value: (id)axisTextColor.CGColor
                       range: strRange];

    // draw the text
    CTLineRef   ctLine    = CTLineCreateWithAttributedString((CFAttributedStringRef)attrString);
    CGFloat     ascent;
    CGFloat     descent;
    CGFloat     width     = ceilf(CTLineGetTypographicBounds(ctLine, &ascent, &descent, NULL));
    CGFloat     height    = ceilf(ascent + descent);
    CGSize      textSize  = CGSizeMake(width, height);
    CGPoint     atPoint   = CGPointMake(dockPoint.x + (1.0 - textSize.width) * rMul,
                                        dockPoint.y + (10.0 - 2.0) * rMul); // x = text right edge, y = text mid
    CGPoint     userPoint = CGContextConvertPointToUserSpace(context, atPoint);

    if (fabsf(tiltLeftAxisX) > 1.0e-8)
    {
        CGContextRotateCTM(context, -tiltLeftAxisX);
        dockPoint.y += 2.0 * rMul;      // offset y 2 points down
        dockPoint = CGContextConvertPointToUserSpace(context, dockPoint);
        dockPoint.x = nearbyintf(dockPoint.x);
        dockPoint.y = nearbyintf(dockPoint.y);
        userPoint = CGPointMake(dockPoint.x - width,
                                dockPoint.y - height / 2.0);
    }

    CGContextSetTextPosition(context, userPoint.x, userPoint.y);
    CTLineDraw(ctLine, context);

    CGRect  rectTempl = CGRectMake(-5.0, -5.0, 10.0, 10.0);
    CGRect  rectDot   = CGRectOffset(rectTempl, userPoint.x, userPoint.y);

    [[UIColor redColor] set];
    CGContextFillEllipseInRect(context, rectDot);
    rectDot = CGRectOffset(rectTempl, atPoint.x, atPoint.y);
    [[UIColor greenColor] set];
    CGContextFillEllipseInRect(context, rectDot);

    // clean up
    CFRelease(ctLine);
    CFRelease(helvetica);
    CGContextRestoreGState(context);
}

---

打印上下文与绘图上下文确实非常不同。因此，上述方法最终有效的结论如下：

- (void)drawAxisValueXin: (CGContextRef)context withText: (NSString*)axisValueX dockToPoint: (CGPoint)dockPoint
{
    BOOL        isRetina  = (!isPrinting && AfxGetApp().isRetina);
    CGFloat     rMul      = (isRetina) ? 2.0 : 1.0;
    CGFloat     fontSize  = 10.0;
    CTFontRef   helvetica = CTFontCreateWithName(CFSTR("Helvetica"), fontSize, NULL);

    if (isRetina)
    {
        dockPoint.x *= 2.0;
        dockPoint.y *= 2.0;
    }
    else if (isPrinting)
    {
        dockPoint.y += 2.0;
    }

    // flip the coordinate system
    CGContextSaveGState(context);

    if (isPrinting)
    {
        CGContextSetTextMatrix(context, CGAffineTransformMakeScale(1.0, -1.0));
    }
    else
    {
        CGContextSetTextMatrix(context, CGAffineTransformIdentity);
        CGContextTranslateCTM(context, 0.0f, CGRectGetHeight(usedBounds) * rMul);
        CGContextScaleCTM(context, 1.0f, -1.0f);
    }

    // make the attributed string
    NSMutableAttributedString*  attrString = [[NSMutableAttributedString alloc] initWithString:axisValueX];
    NSRange                     strRange   = NSMakeRange(0, [attrString length]);

    [attrString addAttribute: (id)kCTFontAttributeName
                       value: (__bridge id)helvetica
                       range: strRange];
    [attrString addAttribute: (id)kCTForegroundColorAttributeName
                       value: (id)axisTextColor.CGColor
                       range: strRange];

    // draw the text
    CTLineRef   ctLine    = CTLineCreateWithAttributedString((CFAttributedStringRef)attrString);
    CGFloat     ascent;
    CGFloat     descent;
    CGFloat     width     = ceilf(CTLineGetTypographicBounds(ctLine, &ascent, &descent, NULL));
    CGFloat     height    = ceilf(ascent + descent);
    CGSize      textSize  = CGSizeMake(width, height);
    CGPoint     atPoint   = CGPointMake(dockPoint.x + (1.0 - textSize.width) * rMul,
                                        dockPoint.y + (10.0 - 2.0) * rMul); // x = text right edge, y = text mid
    CGPoint     userPoint = (isPrinting) ? atPoint : CGContextConvertPointToUserSpace(context, atPoint);

    if (fabsf(tiltLeftAxisX) > 1.0e-8)
    {
        if (isPrinting)
        {
            CGFloat xMove = textSize.height * sin(tiltLeftAxisX);
            CGFloat yMove = textSize.width  * sin(tiltLeftAxisX);

            userPoint.x -= xMove;
            userPoint.y -= yMove;
            userPoint    = CGContextConvertPointToDeviceSpace(context, userPoint);
            CGContextRotateCTM(context, tiltLeftAxisX);
            userPoint    = CGContextConvertPointToUserSpace(context, userPoint);
        }
        else
        {
            CGContextRotateCTM(context, -tiltLeftAxisX);
            dockPoint.y += 2.0 * rMul;      // offset y 2 points down
            dockPoint    = CGContextConvertPointToUserSpace(context, dockPoint);
            dockPoint.x  = nearbyintf(dockPoint.x);
            dockPoint.y  = nearbyintf(dockPoint.y);
            userPoint    = CGPointMake(dockPoint.x - width,
                                       dockPoint.y - height / 2.0);
        }
    }

    CGContextSetTextPosition(context, userPoint.x, userPoint.y);
    CTLineDraw(ctLine, context);

    // clean up
    CFRelease(ctLine);
    CFRelease(helvetica);
    CGContextRestoreGState(context);
}