koffice/krita/ui/canvas

[Adrian Page]

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. ;-)

Adrian