iOS
CGContext Reference

замечания

Строка рисования

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetLineWidth(context, 5.0);
CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
CGContextMoveToPoint(context, 200, 400);
CGContextAddLineToPoint(context, 100, 100);
CGContextStrokePath(context);
CGColorSpaceRelease(colorspace);

Рисовать текст

Draw To требует, чтобы структура Core Text была добавлена ​​на этапе сборки

[NSString* textToDraw = @"Welcome to the world Of IOS";
   
    CFStringRef stringRef = (__bridge CFStringRef)textToDraw;
    
    CFAttributedStringRef currentText = CFAttributedStringCreate(NULL, stringRef, NULL);
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(currentText); 
    CGRect frameRect = CGRectMake(0, 0, 300, 100);
    CGMutablePathRef framePath = CGPathCreateMutable();
    CGPathAddRect(framePath, NULL, frameRect);
    
    CFRange currentRange = CFRangeMake(0, 0);
    CTFrameRef frameRef = CTFramesetterCreateFrame(framesetter, currentRange, framePath, NULL);
    CGPathRelease(framePath); 
    CGContextRef currentContext = UIGraphicsGetCurrentContext();
          
    CGContextSetTextMatrix(currentContext, CGAffineTransformIdentity);
    CGContextTranslateCTM(currentContext, 200, 300);
    CGContextScaleCTM(currentContext, 2, -2);
    CTFrameDraw(frameRef, currentContext);
    
    CFRelease(frameRef);
    CFRelease(stringRef);
    CFRelease(framesetter);