On 01/14/2013 06:04 PM, Thomas Senyk wrote: > On Mon, January 14, 2013 12:54:56 Samuel Rødal wrote: >> On 01/11/2013 04:59 PM, Thomas Senyk wrote: >>> Hi, >>> >>> as with Quick2.0 we got the very nice DistanceField-font-rendering. >>> So in theory animations on Text{ font.pixelSize } should be fairly cheap, >>> right? >>> >>> With the following code snipped I got performance problems never the less: >>> >>> import QtQuick 2.0 >>> Text { >>> >>> id: text >>> width: 500 >>> height: 100 >>> text: "Test font.pixelSize animation" >>> NumberAnimation { >>> >>> running: true >>> loops: Animation.Infinite >>> duration: 2000 >>> target: text >>> property: "font.pixelSize" >>> from: 10 >>> to: 90 >>> >>> } >>> >>> } >>> >>> >>> The strange thing is, on my desktop he has 100% cpu load for the first 2-4 >>> loops. >>> ... I wild guess: It looks like it needs to render the font-glyphs for >>> each(?) size and after a few cycles it got all of them rendered and >>> cached...? (it can't render all of them in the first loop as he jumps due >>> to bad performance) >>> >>> On embedded (raspberry pi) I get <20% load all the time. >>> >>> On desktop I got: >>> - intel xeon 3ghz >>> - nvidia 8600gts >>> - Qt5 checkout from this week, branch: stable >>> - xcb as platform backend (using freetype and fontconfig) >>> >>> On the raspberry I got: >>> - BCM 2835 (slow ARM11 cpu, fast VideoCore IV GPU) >>> - eglfs as platform backend >>> - no fontconfig -> QBasicFontDatabase >>> >>> (If it helps I can do a fontconfig build) >>> >>> Is this know? Can anyone verify? >>> And possible explanation? .. maybe my Qt5 build on desktop is flawed? >> >> Try adding "renderType: Text.QtRendering" in the Text element. On >> desktop it might be that Text.NativeRendering is the default (which does >> not use distance field glyphs but texture glyphs cached based on the >> pixel size, maybe even on the scale?). > > No the default was already "renderType: Text.QtRendering" > > Changing the property does work, as the font is rendered differently with > "renderType: Text.NativeRendering" > (Especially during the animation one can see how the font is changing with > renderType: Text.NativeRendering, e.g. line-width/boldness is jumping) > > > The performance behavior seams to be the same. > First 2-4 cycles it's 100% cpu then is drops to <5% > > > Again from the other side of this thread: > I'm not searching for a quick work-around (e.g. scale), I rather want to > understand why this is happening, why it's different on my rpi and if this is > a bug or a wanted/accepted behavior.
I don't understand it, the distance field text should not be re-generated based on pixelSize. Maybe there's something else going on, since it's on desktop you could run it through callgrind perhaps :) > Greets > Thomas > > p.s.: (a bit off-topic) > @ "cached based even on scale" > Scale with "renderType: Text.NativeRendering" is similar as with Qt4/Quick1: > He renders with the specified font size and scales it during gl-painting > -> "font.pixelSize: 1; scale: 30" looks extremely unreadable. > > Where "renderType: Text.QtRendering" produces the same output with > "font.pixelSize: 1; scale: 30;" and "font.pixelSize: 30; scale: 1;" > (not counting the 'Text' elements geometry properties) Good to know :) -- Samuel _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest