drawAtPoint 不适用于 PDF OS X答案

【问题标题】：drawAtPoint not working for PDF OS XdrawAtPoint 不适用于 PDF OS X
【发布时间】：2016-03-15 16:39:41
【问题描述】：

CGContextShowTextAtPoint 说它已被弃用，所以我想找到一种将文本绘制到 PDF 上下文的替代方法。以下工作（这是我想更改的代码）：

CGPDFContextBeginPage(self.writeContext, pageDictionary);

 //Add text
 CGContextSelectFont(self.writeContext, "Helvetica", 26, kCGEncodingMacRoman);
 CGContextSetTextDrawingMode(self.writeContext, kCGTextFill);
 CGContextSetRGBFillColor(self.writeContext, 0, 0, 0, 1);
 const char *text="Hello Text Test";
 CGContextShowTextAtPoint(self.writeContext, 110, 0, text, strlen(text));

 CGPDFContextEndPage(self.writeContext);

但是这段代码不起作用（页面最终只是空白）

CGPDFContextBeginPage(self.writeContext, pageDictionary);

 //Add text
[@"Hello Text Test" drawAtPoint:CGPointMake(100, 100) withAttributes:@{NSFontAttributeName:[NSFont fontWithName:@"Helvetica" size:24]}];
 //=========

CGPDFContextEndPage(self.writeContext);

【问题讨论】：

标签： objective-c macos pdf

【解决方案1】：

我认为您缺少 NSGraphicsContext

完整代码如下：

NSLog(@"Print PDF");
CFURLRef filePath;
NSSavePanel*    panel = [NSSavePanel savePanel];
[panel setNameFieldStringValue:[self.selectedAccount.name stringByAppendingString:@".pdf"]];
[panel beginSheetModalForWindow:self.window completionHandler:^(NSInteger result){
    if (result == NSFileHandlingPanelOKButton) {

        NSURL*  theFile = [panel URL];
        CGRect mediaBox = CGRectMake(0, 0, 576.0, 576.0);
        CFURLRef saveLocation = CFBridgingRetain(theFile);
        //dictionary to store doc attributes
        CFMutableDictionaryRef attributes = CFDictionaryCreateMutable(NULL,
                                                                      3,
                                                                      &kCFTypeDictionaryKeyCallBacks,
                                                                      &kCFTypeDictionaryValueCallBacks);

        CFDictionaryAddValue(attributes, kCGPDFContextAuthor, CFSTR("Rich Claxton"));
        CFDictionaryAddValue(attributes, kCGPDFContextTitle, CFSTR("This is working"));

        CGContextRef pdfContext = CGPDFContextCreateWithURL(saveLocation, &mediaBox, attributes);

        /** Create NSGraphicsContext !! **/
        NSGraphicsContext* newGC = [NSGraphicsContext graphicsContextWithGraphicsPort:pdfContext flipped:NO];
        [NSGraphicsContext saveGraphicsState];
        [NSGraphicsContext setCurrentContext:newGC];


        CGPDFContextBeginPage(pdfContext, NULL);

        //Draw Strings here
        [@"Hello World !!" drawAtPoint:CGPointMake(2.0,2.0) withAttributes:(NULL)];

        CGPDFContextEndPage(pdfContext);
        CGPDFContextClose(pdfContext);
        CGContextRelease(pdfContext);
    }
}];

【讨论】：