Drawing Text with Core Graphics

Question

I need to draw centered text to a CGContext.

I started with a Cocoa approach. I created a NSCell with the text and tried to draw it thus:

NSGraphicsConte         


        

Answer 1

I finally managed to find answers after 4 days of searching. I really wish Apple makes better documentation. So here we go

I assume you already have CGFontRef with you. If not let me know I will tell you how to load a ttf from resource bundle into CgFontRef.

Below is the code snippet to compute the bounds of any string with any CGFontref

        int charCount = [string length];
        CGGlyph glyphs[charCount];
        CGRect rects[charCount];

        CTFontGetGlyphsForCharacters(theCTFont, (const unichar*)[string cStringUsingEncoding:NSUnicodeStringEncoding], glyphs, charCount);
        CTFontGetBoundingRectsForGlyphs(theCTFont, kCTFontDefaultOrientation, glyphs, rects, charCount);

        int totalwidth = 0, maxheight = 0;
        for (int i=0; i < charCount; i++)
        {
            totalwidth += rects[i].size.width;
            maxheight = maxheight < rects[i].size.height ? rects[i].size.height : maxheight;
        }

        dim = CGSizeMake(totalwidth, maxheight);

Reuse the same function CTFontGetGlyphsForCharacters to get the glyphs. To get a CTFontRef from a CGFontRef use CTFontCreateWithGraphicsFont() function

Also remember NSFont and CGFontRef are toll-free bridged, meaning they can casted into each other and they will work seamlessly without any extra work.