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我與EGOTextView.I設置textContentView for viewForZoomingInScrollView.when我縮小和打字。它有時會返回不正確的高度。下面是我在做什麼：縮小時CTFramesetterSuggestFrameSizeWithConstraints返回不正確的高度？
CTFramesetterRef framesetter = _framesetter;
CFAttributedStringRef attributedStringRef=(CFAttributedStringRef)self.attributedString;
_framesetter = CTFramesetterCreateWithAttributedString(attributedStringRef);
if (framesetter!=NULL) {
CFRelease(framesetter);
}
CGRect rect = self.textContextView.frame;
CGFloat height = [self heightForAttributedString:self.attributedString forWidth:rect.size.width];
rect.size.height = (height + self.font.lineHeight * 2) * pageScale;
//pageScale is the scale scrollview end zooming
- (CGFloat)boundingHeightForWidth:(CGFloat)width {
CGSize suggestedSize = CTFramesetterSuggestFrameSizeWithConstraints(_framesetter, CFRangeMake(0, 0), NULL, CGSizeMake(width , CGFLOAT_MAX), NULL);
return suggestedSize.height;
}
我試試這個方法太：
+(CGFloat)heightForAttributedString:(NSAttributedString *)attrString forWidth:(CGFloat)inWidth
{
CGFloat H = 0;
// Create the framesetter with the attributed string.
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFMutableAttributedStringRef) attrString);
CGRect box = CGRectMake(0,0, inWidth, CGFLOAT_MAX);
CFIndex startIndex = 0;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, box);
// Create a frame for this column and draw it.
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(startIndex, 0), path, NULL);
// Start the next frame at the first character not visible in this frame.
//CFRange frameRange = CTFrameGetVisibleStringRange(frame);
//startIndex += frameRange.length;
CFArrayRef lineArray = CTFrameGetLines(frame);
CFIndex j = 0, lineCount = CFArrayGetCount(lineArray);
CGFloat h, ascent, descent, leading;
for (j=0; j < lineCount; j++)
{
CTLineRef currentLine = (CTLineRef)CFArrayGetValueAtIndex(lineArray, j);
CTLineGetTypographicBounds(currentLine, &ascent, &descent, &leading);
h = ascent + descent + leading;
NSLog(@"%f", h);
H+=h;
}
CFRelease(frame);
CFRelease(path);
CFRelease(framesetter);
return H;
}
但它似乎總是返回一個錯誤的高度，當你放大後輸入文字。 有沒有其他的/更好的方法來找出我的屬性字符串的正確高度？謝謝！