如何以编程方式在iOS中创建PDF？

Question

我想在iOS中创建一个PDF文件,PDF中应该有一个表,它从一个数组中填充.我已经在Google上搜索过,但没有成功.任何帮助表示赞赏

Answer 1

像这样的例程来渲染文本：

- (CFRange)renderTextRange:(CFRange)currentRange andFrameSetter:(CTFramesetterRef)frameSetter intoRect:(CGRect)frameRect {
CGMutablePathRef framePath = CGPathCreateMutable();
CGPathAddRect(framePath, NULL, frameRect);
CTFrameRef frameRef = CTFramesetterCreateFrame(frameSetter, currentRange, framePath, NULL);
CGContextRef currentContext = UIGraphicsGetCurrentContext();
CGContextSaveGState(currentContext);
CGContextSetTextMatrix(currentContext, CGAffineTransformIdentity);  
CGContextTranslateCTM(currentContext, 0, 792); 
CGContextScaleCTM(currentContext, 1.0, -1.0);
CTFrameDraw(frameRef, currentContext);
CGContextRestoreGState(currentContext);
CGPathRelease(framePath);
currentRange = CTFrameGetVisibleStringRange(frameRef);
currentRange.location += currentRange.length;
currentRange.length = 0;
CFRelease(frameRef);
return currentRange;
}

下面的代码片段调用它，假设您已创建上下文和任何字体等并在适当的变量中。以下循环只是将文本逐行构建到NSMutableAttributedString您可以渲染的文本中：

CTFontRef splainFont = CTFontCreateWithName(CFSTR("Helvetica"), 10.0f, NULL);
CGFloat margin = 32.0f;
CGFloat sink = 8.0f;

NSMutableAttributedString *mainAttributedString = [[NSMutableAttributedString alloc] init];
NSMutableString *mainString = [[NSMutableString alloc] init];

// Ingredients is an NSArray of NSDictionaries
// But yours could be anything, or just an array of text.
for (Ingredient *ingredient in ingredients) {
    NSString *ingredientText = [NSString stringWithFormat:@"%@\t%@
        \n",ingredient.amount,ingredient.name];
    [mainString appendString:ingredientText];
    NSMutableAttributedString *ingredientAttributedText =
        [[NSMutableAttributedString alloc] initWithString:ingredientText];
    [ingredientAttributedText addAttribute:(NSString *)(kCTFontAttributeName)
        value:(id)splainFont
        range:NSMakeRange(0, [ingredientText length])];
    [mainAttributedString appendAttributedString:ingredientAttributedText];
    [ingredientAttributedText release];
}

现在，您已将数组用换行符写出，NSMutableAttributedString您可以渲染它，根据您的文本，您可能希望在循环中渲染它，直到渲染的位置与您的文本长度匹配。就像是：

// Render Main text.
CTFramesetterRef mainSetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)mainAttributedString);
currentRange = [KookaDIS renderTextRange:currentRange 
    andFrameSetter:mainSetter 
    intoRect:pageRect];

// If not finished create new page and loop until we are.
while (!done) {
    UIGraphicsBeginPDFPageWithInfo(pageRect, nil);

    currentRange = [self renderTextRange:currentRange 
        andFrameSetter:mainSetter 
        intoRect:pageRect];

    if (currentRange.location >= [mainString length]) {
        done = TRUE;
    }
}

上面的代码需要相当多的调整，我确信它是从我自己的项目中破解出来的，所以一些变量（如框架设置器）将不存在，你需要关闭 PDF 上下文并释放变量等. 注意如何使用 mainString 来确定文本何时被渲染出来。

它应该足够清楚地指示如何循环数组或任何其他组以将任意长度的文本呈现到文档中。

对 while 循环和输入之前的渲染稍加修改也可以让您在多列中渲染文本。