koffice/krita/ui/canvas

[Boudewijn Rempt]

On Sunday 31 January 2010, Adrian Page wrote:
> Dmitry Kazakov wrote:
> > I thing this should be reverted according to Qt's QRect tradition, i.e.
> > (5,7)->(5.0,7.0). Or change ALL the Krita's code that uses
> > QRectF::toAlignedRect() or QRectF(intRect) to a new type of conversion.
> > Other way we'll dig a deep grave for ourselves using two completely
> > different coordinate systems throughout the code.
> 
> This is the way krita has worked for the last however many years. The
> standard in graphics is that when you convert int to floating point you
> add 0.5, and you truncate when converting float to int. (5, 7) -> (5.5,
> 7.5) -> (5, 7). We use subpixel positioning, so a 1x1 pixel brush
> painted to cover the top-left pixel is rendered at (0.5, 0.5), the
> centre of that pixel. Rendering it at (0.0, 0.0) will divide the brush
> over the 4 pixels (-1, -1), (-1, 0), (0, -1) and (0, 0).
> 
> krita already has functions that perform these conversions, see
> KisImage::pixelToDocument(const QPoint &) and KisTool::*. And krita was
> doing this before QPointF/QRectF even existed, so we're hardly breaking
> with their tradition. ;-)

Aol.

-- 
Boudewijn Rempt | http://www.valdyas.org