我正在使用CoreText在MAC OS X上實現自定義文本佈局算法。我必須在自定義NSView子類對象內的不同位置部分渲染CTRun的一部分。CTRunDraw()確實實現了正確的行爲
這是我實現的drawRect:方法
- (void)drawRect:(NSRect)dirtyRect {
// Drawing code here.
CGContextRef context =
(CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
CGContextSaveGState(context); {
[[NSColor whiteColor] set];
NSRectFill(dirtyRect);
CTFontRef font = CTFontCreateWithName(CFSTR("Menlo"), 20, &CGAffineTransformIdentity);
CFTypeRef values[] = {font};
CFStringRef keys[] = {kCTFontAttributeName};
CFDictionaryRef dictionary =
CFDictionaryCreate(NULL,
(const void **)&keys,
(const void **)&values,
sizeof(keys)/sizeof(keys[0]),
&kCFTypeDictionaryKeyCallBacks,
&kCFTypeDictionaryValueCallBacks);
CFAttributedStringRef longString =
CFAttributedStringCreate(kCFAllocatorDefault, CFSTR("this_is_a_very_long_string_that_compromises_many_glyphs,we_wil_see_it:)"), dictionary);
CTLineRef lineRef = CTLineCreateWithAttributedString(longString);
CFArrayRef runsArray = CTLineGetGlyphRuns(lineRef);
CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(runsArray, 0);
CGAffineTransform textTransform = CGAffineTransformIdentity;
textTransform = CGAffineTransformScale(textTransform, 1.0, -1.0);
CGContextSetTextMatrix(context, textTransform);
CGAffineTransform sequenceTransform =
CGAffineTransformIdentity;
sequenceTransform = CGAffineTransformTranslate(sequenceTransform, 0, 23.2818);
CGPoint firstPoint = CGPointApplyAffineTransform(CGPointMake(0, 0), sequenceTransform);
CFRange firstRange = CFRangeMake(0, 24);
CGContextSetTextPosition(context, firstPoint.x, firstPoint.y);
CTRunDraw(run, context, firstRange);
CGPoint secondPoint = CGPointApplyAffineTransform(CGPointMake(0, 26.2812), sequenceTransform);
CFRange secondRange = CFRangeMake(24, 24);
CGContextSetTextPosition(context, secondPoint.x, secondPoint.y);
CTRunDraw(run, context, secondRange);
CGPoint thirdPoint = CGPointApplyAffineTransform(CGPointMake(0, 52.5625), sequenceTransform);
CFRange thirdRange = CFRangeMake(48, 23);
CGContextSetTextPosition(context, thirdPoint.x, thirdPoint.y);
CTRunDraw(run, context, thirdRange);
}
CGContextRestoreGState(context);
}
下面是該代碼 https://docs.google.com/open?id=0B8df1OdxKw4FYkE5Z1d1VUZQYWs
的問題是CTRunDraw的輸出()方法插入的位置空白除了指定的範圍。
我想要的是它應該使運行的部分在其正確的位置。 這裏是我想要的正確的輸出(正確的輸出是原始輸出的photoshop)。 https://docs.google.com/open?id=0B8df1OdxKw4FcFRnS0p1cFBfa28
注:我在我的自定義NSView子類中使用翻轉座標系。
- (BOOL)isFlipped {
return YES;
}