50528 2010-12-04 15:01:38 -0800 SVG text smaller than 0.5px not displayed properly 2011-02-01 10:06:53 -0800 1 1 1 Unclassified WebKit SVG 528+ (Nightly build) PC OS X 10.5 RESOLVED DUPLICATE 12448 http://http://codedread.com/browser-tests/subpixel.svg P2 Normal --- 0 jeffschiller webkit-unassigned krit simon.fraser zimmermann oldest_to_newest 317315 0 jeffschiller 2010-12-04 15:01:38 -0800 http://codedread.com/browser-tests/subpixel.svg or <svg xmlns='http://www.w3.org/2000/svg'> <text x='10' y='30'>The two words should be the same size:</text> <g transform='scale(15)'> <text y='12' style='font-size:0.5px'>TINY</text> <text y='24' style='font-size:0.499999px'>TINY</text> </g> </svg> Both words should be small on the page. The latter one at font-size smaller than 0.5px is not displayed appropriately. Also, you can see the effect more dramatically here: http://upload.wikimedia.org/wikipedia/commons/f/f9/PI.svg 317316 1 75617 jeffschiller 2010-12-04 15:03:29 -0800 Created attachment 75617 Test case showing the problem 319322 2 zimmermann 2010-12-09 01:13:05 -0800 Thanks for the testcase, Jeff! I've traced it down: #1 0x0426c654 in WebCore::FontCache::createFontPlatformData (this=0x1a5965c0, fontDescription=@0x1d4adda0, family=@0x1d4adda0) at /Users/nikolaszimmermann/Coding/WebKit/WebCore/platform/graphics/mac/FontCacheMac.mm:214 (gdb) p fontDescription $61 = (const class WebCore::FontDescription &) @0x1d4adda0: { m_familyList = { m_family = { m_string = { m_impl = { <WTF::FastAllocBase> = {<No data fields>}, members of WTF::RefPtr<WTF::StringImpl>: m_ptr = 0x1a56e650 } } }, m_next = { <WTF::RefPtr<WebCore::SharedFontFamily>> = { <WTF::FastAllocBase> = {<No data fields>}, members of WTF::RefPtr<WebCore::SharedFontFamily>: m_ptr = 0x0 }, <No data fields>} }, m_specifiedSize = 0.49000001, m_computedSize = 0.49000001, The font size is stored correctly in the FontDescription, but then "computedPixelSize()" is used to determine the actual font size. 193 194 FontPlatformData* FontCache::createFontPlatformData(const FontDescription& fontDescription, const AtomicString& family) 195 { 196 NSFontTraitMask traits = fontDescription.italic() ? NSFontItalicTrait : 0; 197 NSInteger weight = toAppKitFontWeight(fontDescription.weight()); 198 float size = fontDescription.computedPixelSize(); (gdb) p size $63 = 0 FontDescription.h: int computedPixelSize() const { return int(m_computedSize + 0.5f); } This is the root of the problem. Just keeping my analysis here for the record. 343123 3 zimmermann 2011-02-01 04:02:52 -0800 The patch on bug 12448 fixes this problem. Thanks a lot for the testcase, I've integrated it in my patch. *** This bug has been marked as a duplicate of bug 12448 *** 343240 4 simon.fraser 2011-02-01 08:44:35 -0800 Is it really the same thing? In this testcase the text is just a line of pixels (even if it's not sharp). In Firefox, the text is much bigger. 343278 5 zimmermann 2011-02-01 09:49:33 -0800 (In reply to comment #4) > Is it really the same thing? In this testcase the text is just a line of pixels (even if it's not sharp). In Firefox, the text is much bigger. Which testcase are you referring to? 343287 6 simon.fraser 2011-02-01 10:00:07 -0800 One in a bug that I can't find right now, but was probably marked as a duplicate of this. 343291 7 krit 2011-02-01 10:03:20 -0800 I guess Simon thought about bug 52892. 343295 8 simon.fraser 2011-02-01 10:06:53 -0800 Yep, that's the one. Sorry, I thought this was that bug. 75617 2010-12-04 15:03:29 -0800 2010-12-04 15:03:29 -0800 Test case showing the problem subpixel.svg image/svg+xml 271 jeffschiller PHN2ZyB4bWxucz0naHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmcnPgogIDx0ZXh0IHg9JzEwJyB5 PSczMCc+VGhlIHR3byB3b3JkcyBzaG91bGQgYmUgdGhlIHNhbWUgc2l6ZTo8L3RleHQ+CiAgPHRl eHQgeD0nMTAnIHk9JzEyJyB0cmFuc2Zvcm09J3NjYWxlKDE1KSc+CiAgICA8dHNwYW4gc3R5bGU9 J2ZvbnQtc2l6ZTowLjVweCc+VElOWTwvdHNwYW4+CiAgICA8dHNwYW4gc3R5bGU9J2ZvbnQtc2l6 ZTowLjQ5OTk5OXB4Jz5USU5ZPC90c3Bhbj4KICA8L3RleHQ+Cjwvc3ZnPg==