创建多页 PDF 时出错

Question

有人已经在 iPad 应用程序中创建了 PDF 文档吗？我看到 UIKit 中有新函数可以执行此操作，但我找不到任何代码示例。

BOOL UIGraphicsBeginPDFContextToFile (
   NSString *path,
   CGRect bounds,
   NSDictionary *documentInfo
);

void UIGraphicsBeginPDFPage (
   void
);

我找到了一个应该在 iPhone 上运行的示例，但这给了我错误：

Fri Apr 30 11:55:32 wks104.hs.local PDF[1963] <Error>: CGFont/Freetype: The function `create_subset' is currently unimplemented.
Fri Apr 30 11:55:32 wks104.hs.local PDF[1963] <Error>: invalid Type1 font: unable to stream font.
Fri Apr 30 11:55:32 wks104.hs.local PDF[1963] <Error>: FT_Load_Glyph failed: error 6.
Fri Apr 30 11:55:32 wks104.hs.local PDF[1963] <Error>: FT_Load_Glyph failed: error 6.
Fri Apr 30 11:55:32 wks104.hs.local PDF[1963] <Error>: FT_Load_Glyph failed: error 6.
Fri Apr 30 11:55:32 wks104.hs.local PDF[1963] <Error>: FT_Load_Glyph failed: error 6.

Answer 1

实际上，我通过修改上面的代码来创建多页 PDF，例如：

- (void) createPDF:(NSString *)fileName withContent:(NSString *)content forSize:(int)fontSize andFont:(NSString *)font andColor:(UIColor *)color {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *newFilePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:fileName];

CGRect a4Page = CGRectMake(0, 0, DOC_WIDTH, DOC_HEIGHT);

NSDictionary *fileMetaData = [[NSDictionary alloc] init];

if (!UIGraphicsBeginPDFContextToFile(newFilePath, a4Page, fileMetaData )) {
    NSLog(@"error creating PDF context");
    return;
}

BOOL done = NO;

CGContextRef context = UIGraphicsGetCurrentContext();

CFRange currentRange = CFRangeMake(0, 0);

CGContextSetTextDrawingMode (context, kCGTextFill);
CGContextSelectFont (context, [font cStringUsingEncoding:NSUTF8StringEncoding], fontSize, kCGEncodingMacRoman);                                                 
CGContextSetFillColorWithColor(context, [color CGColor]);
// Initialize an attributed string.
CFMutableAttributedStringRef attrString = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
CFAttributedStringReplaceString (attrString, currentRange, (CFStringRef)content);

// Create the framesetter with the attributed string.
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attrString);

do {
    UIGraphicsBeginPDFPage();



    CGMutablePathRef path = CGPathCreateMutable();

    CGRect bounds = CGRectMake(LEFT_MARGIN, 
                               TOP_MARGIN, 
                               DOC_WIDTH - RIGHT_MARGIN - LEFT_MARGIN, 
                               DOC_HEIGHT - TOP_MARGIN - BOTTOM_MARGIN);

    CGPathAddRect(path, NULL, bounds);



    // Create the frame and draw it into the graphics context
    CTFrameRef frame = CTFramesetterCreateFrame(framesetter, currentRange, path, NULL);

    if(frame) {
        CGContextSaveGState(context);
        CGContextTranslateCTM(context, 0, bounds.origin.y); 
        CGContextScaleCTM(context, 1, -1); 
        CGContextTranslateCTM(context, 0, -(bounds.origin.y + bounds.size.height)); 
        CTFrameDraw(frame, context);
        CGContextRestoreGState(context); 

        // Update the current range based on what was drawn.
        currentRange = CTFrameGetVisibleStringRange(frame);
        currentRange.location += currentRange.length;
        currentRange.length = 0;

        CFRelease(frame);       
    }

    // If we're at the end of the text, exit the loop.
    if (currentRange.location == CFAttributedStringGetLength((CFAttributedStringRef)attrString))
        done = YES;
}
while(!done);

UIGraphicsEndPDFContext();

[fileMetaData release];
CFRelease(attrString);
CFRelease(framesetter);
}

但是，如上所述，它忽略了我尝试设置的字体。我总是得到一些看起来像“Helvetica”的东西。

那么，目前没有办法在 iPad/iPhone 上创建嵌入设备上使用的字体的 PDF 文件吗？我简直不敢相信。我至少希望支持那些“常见的”字体，例如：Courier、Times New Roman 等。

如果有人有更多信息或有关解决方法的有用提示，欢迎分享。

提前致谢。

Answer 2

这是创建新 PDF 文档的方法。但它不进行文本格式化。

    - (void) createNewPDF: (NSString *) saveFileName withContent: (NSString *) content forSize: (int) fontSize andFont:(NSString *) font andColor: (UIColor *) color
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *newFilePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:saveFileName];

    CGRect a4Page = CGRectMake(0, 0, 595, 842);

    NSDictionary *fileMetaData = [[NSDictionary alloc] init];

    if (!UIGraphicsBeginPDFContextToFile(newFilePath, a4Page, fileMetaData )) {
        NSLog(@"error creating PDF context");
        return;
    }

    CGContextRef mpdfContext = UIGraphicsGetCurrentContext();
    UIGraphicsBeginPDFPage();
    CGContextSetTextMatrix(mpdfContext, CGAffineTransformMake(1, 0, 0, -1, 0, 0));
    CGContextSetTextDrawingMode (mpdfContext, kCGTextFill);
    CGContextSelectFont (mpdfContext, [font cStringUsingEncoding:NSUTF8StringEncoding], fontSize, kCGEncodingMacRoman);                                                 
    CGContextSetFillColorWithColor(mpdfContext, [color CGColor]);
    CGContextShowTextAtPoint (mpdfContext, 20, 20, [content cStringUsingEncoding:NSUTF8StringEncoding], [content length]);
    UIGraphicsEndPDFContext();

}

Answer 3

只是为了让您知道错误消息：

无效的 Type1 字体：无法流式传输字体

以及：
FT_Load_Glyph 失败：错误 6.

在 iOS 4.2 中消失

Answer 4

这是一个更好的解决方案，因为它使用正确的坐标变换来使文本从上到下打印。

#define LEFT_MARGIN 25
#define RIGHT_MARGIN 25
#define TOP_MARGIN 35
#define BOTTOM_MARGIN 50
#define BOTTOM_FOOTER_MARGIN 32
#define DOC_WIDTH 595
#define DOC_HEIGHT 842

- (void) createPDF:(NSString *)fileName withContent:(NSString *)content forSize:(int)fontSize andFont:(NSString *)font andColor:(UIColor *)color
{

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *newFilePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:fileName];

    CGRect a4Page = CGRectMake(0, 0, DOC_WIDTH, DOC_HEIGHT);

    NSDictionary *fileMetaData = [[NSDictionary alloc] init];

    if (!UIGraphicsBeginPDFContextToFile(newFilePath, a4Page, fileMetaData )) {
        NSLog(@"error creating PDF context");
        return;
    }

    CGContextRef context = UIGraphicsGetCurrentContext();
    UIGraphicsBeginPDFPage();

    CGContextSetTextDrawingMode (context, kCGTextFill);
    CGContextSelectFont (context, [font cStringUsingEncoding:NSUTF8StringEncoding], fontSize, kCGEncodingMacRoman);                                                 
    CGContextSetFillColorWithColor(context, [color CGColor]);

    CGMutablePathRef path = CGPathCreateMutable();

    CGRect bounds = CGRectMake(LEFT_MARGIN, 
                               TOP_MARGIN, 
                               DOC_WIDTH - RIGHT_MARGIN - LEFT_MARGIN, 
                               DOC_HEIGHT - TOP_MARGIN - BOTTOM_MARGIN
                               );

    CGPathAddRect(path, NULL, bounds);

    // Initialize an attributed string.
    CFMutableAttributedStringRef attrString =
    CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
    CFAttributedStringReplaceString (attrString, CFRangeMake(0, 0), (CFStringRef)content);

    // Create the framesetter with the attributed string.
    CTFramesetterRef framesetter =
    CTFramesetterCreateWithAttributedString(attrString);

    // Create the frame and draw it into the graphics context
    CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);
    CFRange visibleRange = CTFrameGetVisibleStringRange(frame);

    if (visibleRange.length < [content length] ) {
        NSLog(@"WARNING: Not all displayed on a single page");
    }

    CFRelease(attrString);
    CFRelease(framesetter);

    if(frame) {
        CGContextSaveGState(context);
        CGContextTranslateCTM(context, 0, bounds.origin.y); 
        CGContextScaleCTM(context, 1, -1); 
        CGContextTranslateCTM(context, 0, -(bounds.origin.y + bounds.size.height)); 
        CTFrameDraw(frame, context);
        CGContextRestoreGState(context); 
        CFRelease(frame);       
    }

    UIGraphicsEndPDFContext();

    [fileMetaData release];
}