使用 UIPrintPageRenderer 在打印的 pdf 中绘制水平线

发布于 2024-11-19 23:50:14 字数 1052 浏览 5 评论 0原文

我正在使用 UIPrintPageRenderer 子类在 pdf 上打印 html 内容。如何在打印内容（页眉和页脚）上添加水平线？

CGContextAddLineToPoint 似乎不适用于 UIPrintPageRenderer 方法。特别是那些用于绘制页眉和页脚的。 NSString 的drawAtPoint 工作完美。

到目前为止，这是我尝试过的：

- (void)drawHeaderForPageAtIndex:(NSInteger)pageIndex inRect:(CGRect)headerRect {
    ...

    // Attempt 1 (Doesn't work!)
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetRGBFillColor(context, 1.0f, 1.0f, 1.0f, 1);
    CGContextSetRGBStrokeColor(context, 1.0f, 1.0f, 1.0f, 1);
    CGContextMoveToPoint(context, 10.0, 20.0);
    CGContextAddLineToPoint(context, 310.0, 20.0);

    // Attempt 2 (Doesn't work!)
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetRGBFillColor(context, 1.0f, 1.0f, 1.0f, 1);
    CGContextSetRGBStrokeColor(context, 1.0f, 1.0f, 1.0f, 1);

    CGContextTranslateCTM(context, 0, headerRect.size.height);
    CGContextScaleCTM(context, 1, -1);

    CGContextMoveToPoint(context, 10.0, 20.0);
    CGContextAddLineToPoint(context, 310.0, 20.0);
}

原文

I'm using UIPrintPageRenderer sub-class to print html content on a pdf. How can i add a horizontal line on my printed content (both on header and footer)?

CGContextAddLineToPoint doesn't seem to work in UIPrintPageRenderer methods. Specifically those used to draw header and footer. NSString's drawAtPoint is working perfectly.

Here's what i've tried so far:

- (void)drawHeaderForPageAtIndex:(NSInteger)pageIndex inRect:(CGRect)headerRect {
    ...

    // Attempt 1 (Doesn't work!)
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetRGBFillColor(context, 1.0f, 1.0f, 1.0f, 1);
    CGContextSetRGBStrokeColor(context, 1.0f, 1.0f, 1.0f, 1);
    CGContextMoveToPoint(context, 10.0, 20.0);
    CGContextAddLineToPoint(context, 310.0, 20.0);

    // Attempt 2 (Doesn't work!)
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetRGBFillColor(context, 1.0f, 1.0f, 1.0f, 1);
    CGContextSetRGBStrokeColor(context, 1.0f, 1.0f, 1.0f, 1);

    CGContextTranslateCTM(context, 0, headerRect.size.height);
    CGContextScaleCTM(context, 1, -1);

    CGContextMoveToPoint(context, 10.0, 20.0);
    CGContextAddLineToPoint(context, 310.0, 20.0);
}

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方圜几里 2024-11-26 23:50:14

在Core Graphics中，逻辑图形元素被添加到上下文中然后绘制。我看到您使用例如 CGContextAddLineToPoint(context, 310.0, 20.0); 添加了上下文的路径

，这会在内存中创建路径，但要将其合成到屏幕上，您需要填充或描边上下文的小路。尝试在实际添加路径之后添加 CGContextStrokePath(context); 。

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梅倚清风 2024-11-26 23:50:14

就像常规绘图一样，

- (void)drawHeaderForPageAtIndex:(NSInteger)pageIndex inRect:(CGRect)headerRect {

    CGContextRef context = UIGraphicsGetCurrentContext();

    CContextMoveToPoint(context, CGRectGetMinX(headerRect), 70);
    CGContextAddLineToPoint(context, CGRectGetMaxX(headerRect), 70);

    CGFloat grayScale = 0.5f;
    CGContextSetRGBStrokeColor(context, grayScale, grayScale, grayScale, 1);

    CGContextStrokePath(context);
}

不要忘记 CGStrokePath(...)

Just as regular drawing

- (void)drawHeaderForPageAtIndex:(NSInteger)pageIndex inRect:(CGRect)headerRect {

    CGContextRef context = UIGraphicsGetCurrentContext();

    CContextMoveToPoint(context, CGRectGetMinX(headerRect), 70);
    CGContextAddLineToPoint(context, CGRectGetMaxX(headerRect), 70);

    CGFloat grayScale = 0.5f;
    CGContextSetRGBStrokeColor(context, grayScale, grayScale, grayScale, 1);

    CGContextStrokePath(context);
}

Don't forget to CGStrokePath(...)

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羞稚 2024-11-26 23:50:14

所以，现在我已经应用了替代解决方案。我仍然很想知道如何使用 CGContext 来做到这一点（无需加载图像）。这是我的解决方案：

// Draw horizontal ruler in the header
UIImage *horizontalRule = [UIImage imageNamed:@"HorizontalRule.png"];
horizontalRule = [horizontalRule stretchableImageWithLeftCapWidth:0.5 topCapHeight:0];

CGFloat rulerX = CGRectGetMinX(headerRect) + HEADER_LEFT_TEXT_INSET;
CGFloat rulerY = self.printableRect.origin.y + fontSize.height + HEADER_FOOTER_MARGIN_PADDING + PRINT_RULER_MARGIN_PADDING;
CGFloat rulerWidth = headerRect.size.width - HEADER_LEFT_TEXT_INSET - HEADER_RIGHT_TEXT_INSET;
CGFloat rulerHeight = 1;
CGRect ruleRect = CGRectMake(rulerX, rulerY, rulerWidth, rulerHeight);

[horizontalRule drawInRect:ruleRect blendMode:kCGBlendModeNormal alpha:1.0];

So, for now i've applied an alternate solution. I would still love to know how to do this using CGContext (without having to load an image). Here's my solution:

// Draw horizontal ruler in the header
UIImage *horizontalRule = [UIImage imageNamed:@"HorizontalRule.png"];
horizontalRule = [horizontalRule stretchableImageWithLeftCapWidth:0.5 topCapHeight:0];

CGFloat rulerX = CGRectGetMinX(headerRect) + HEADER_LEFT_TEXT_INSET;
CGFloat rulerY = self.printableRect.origin.y + fontSize.height + HEADER_FOOTER_MARGIN_PADDING + PRINT_RULER_MARGIN_PADDING;
CGFloat rulerWidth = headerRect.size.width - HEADER_LEFT_TEXT_INSET - HEADER_RIGHT_TEXT_INSET;
CGFloat rulerHeight = 1;
CGRect ruleRect = CGRectMake(rulerX, rulerY, rulerWidth, rulerHeight);

[horizontalRule drawInRect:ruleRect blendMode:kCGBlendModeNormal alpha:1.0];

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