iPhone - 使用CGContextShowTextAtPoint绘制特殊字符
我正在为 UILabel 创建子类来调整字符间距。效果很好。 但是当我在西班牙语或日语中使用特殊字符时，它就不是写作。只有英文字符才能正确书写。关于如何显示它们有什么解决方案吗？
- (void) drawRect:(CGRect)rect
{
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSelectFont (context, [self.font.fontName cStringUsingEncoding:NSUTF8StringEncoding], self.font.pointSize, kCGEncodingMacRoman);
CGContextSetCharacterSpacing(context, -1);
CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);
CGAffineTransform myTextTransform = CGAffineTransformScale(CGAffineTransformIdentity, 1.f, -1.f );
CGContextSetTextMatrix (context, myTextTransform);
// draw 1 but invisbly to get the string length.
const char* str = [self.text UTF8String];
CGPoint p = CGContextGetTextPosition(context);
float centeredY = (self.font.pointSize + (self.frame.size.height - self.font.pointSize)/2)-2;
CGContextShowTextAtPoint(context, 0, centeredY, str, [self.text length]);
CGPoint v = CGContextGetTextPosition(context);
float centeredX = 0;
if (self.centered) {
float width = v.x - p.x;
centeredX = (self.frame.size.width- width)/2;
}
// calculate width and draw second one.
CGContextSetFillColorWithColor(context, [self.textColor CGColor]);
CGContextShowTextAtPoint(context, centeredX, centeredY, str, [self.text length]);
}
I am creating sub class for UILabel to adjust the character spacing. It works well.
But when I use special characters as in Spanish or Japanese language, its not writing. Only english characters are written properly. Any solution on how to display them?
- (void) drawRect:(CGRect)rect
{
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSelectFont (context, [self.font.fontName cStringUsingEncoding:NSUTF8StringEncoding], self.font.pointSize, kCGEncodingMacRoman);
CGContextSetCharacterSpacing(context, -1);
CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);
CGAffineTransform myTextTransform = CGAffineTransformScale(CGAffineTransformIdentity, 1.f, -1.f );
CGContextSetTextMatrix (context, myTextTransform);
// draw 1 but invisbly to get the string length.
const char* str = [self.text UTF8String];
CGPoint p = CGContextGetTextPosition(context);
float centeredY = (self.font.pointSize + (self.frame.size.height - self.font.pointSize)/2)-2;
CGContextShowTextAtPoint(context, 0, centeredY, str, [self.text length]);
CGPoint v = CGContextGetTextPosition(context);
float centeredX = 0;
if (self.centered) {
float width = v.x - p.x;
centeredX = (self.frame.size.width- width)/2;
}
// calculate width and draw second one.
CGContextSetFillColorWithColor(context, [self.textColor CGColor]);
CGContextShowTextAtPoint(context, centeredX, centeredY, str, [self.text length]);
}
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CGContextShowTextAtPoint 不直接支持这些语言——MacRoman 编码可能是一个提示。 CG只有基本的文字布局/绘图。
两个替代方案是 Cocoa 的文本绘制或 CoreText。
CGContextShowTextAtPointdoes not directly support those languages -- the MacRoman encoding may have been a hint. CG has only basic text layout/drawing.two alternatives would be Cocoa's text drawing, or CoreText.
迟到总比不到好；
使用 CoreText 来绘制字体（特殊字符和 Unicode）
http://developer.apple.com/library/ios/#documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_text/dq_text.html#//apple_ref/doc/uid/TP30001066-CH213-TPXREF101
“iOS 3.2 及更高版本和 Mac OS X 都支持 Core Text，这是一种用于布局文本和处理字体的高级低级技术。Core Text 专为高性能和易用性而设计，允许您将 Unicode 文本直接绘制到图形中如果您正在编写需要精确控制文本显示方式的应用程序，请参阅核心文本编程指南。”
Better late than never;
Use CoreText to drawFonts instead (Special characters and Unicode)
http://developer.apple.com/library/ios/#documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_text/dq_text.html#//apple_ref/doc/uid/TP30001066-CH213-TPXREF101
"iOS 3.2 and later and Mac OS X both support Core Text, an advanced low-level technology for laying out text and handing fonts. Core Text is designed for high performance and ease of use and allows you to draw Unicode text directly to a graphics context. If you are writing an application that needs precise control over how text is displayed, see Core Text Programming Guide."