D20255: Improve behavior of rotated displays

zzag added inline comments.

INLINE COMMENTS

> drm_output.cpp:130
>  
> -qreal orientationToRotation(Qt::ScreenOrientation orientation)
> +int orientationToRotation(Qt::ScreenOrientation orientation)
>  {

Could you please explain this change?

> drm_output.cpp:147
>  
> +QMatrix4x4&& DrmOutput::matrixDisplay(const QSize &s) const
> +{

QMatrix4x4 &&

> drm_output.cpp:152
> +    if (angle) {
> +        const QSize center = s/2;
> +

Please follow coding style.

`s / 2`

> drm_output.cpp:181
>  {
> -    QMatrix4x4 matrix;
> -    QMatrix4x4 hotspotMatrix;
> -    if (orientation() != Qt::LandscapeOrientation) {
> -        auto rotation = orientationToRotation(orientation());
> -        matrix.translate(pixelSize().width() /2.0, pixelSize().height() / 2.0);
> -        matrix.rotate(rotation, 0.0f, 0.0f, 1.0f);
> -        matrix.translate(-pixelSize().width() /2.0, -pixelSize().height() / 2.0);
> -        const auto cursorSize = m_backend->softwareCursor().size();
> -        hotspotMatrix.translate(cursorSize.width()/2.0, cursorSize.height()/2.0);
> -        hotspotMatrix.rotate(rotation, 0.0f, 0.0f, 1.0f);
> -        hotspotMatrix.translate(-cursorSize.width()/2.0, -cursorSize.height()/2.0);
> -    }
> -    hotspotMatrix.scale(scale());
> -    matrix.scale(scale());
> -    const auto outputGlobalPos = AbstractOutput::globalPos();
> -    matrix.translate(-outputGlobalPos.x(), -outputGlobalPos.y());
> -    const QPoint p = matrix.map(globalPos) - hotspotMatrix.map(m_backend->softwareCursorHotspot());
> +    const auto hotspotMatrix = matrixDisplay(m_backend->softwareCursor().size());
> +

I'd say that's abuse of `auto` even though the name contains "Matrix".

> drm_output.cpp:185
> +    switch(orientation()) {
> +        case Qt::PrimaryOrientation:
> +        case Qt::LandscapeOrientation:

Please don't indent `case`s.

> drm_output.cpp:189
> +        case Qt::PortraitOrientation:
> +            p = QPoint(p.ry(), pixelSize().height() - p.rx());
> +            break;

Why `ry` and `rx`?

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D20255

To: apol, #kwin
Cc: zzag, kwin, jraleigh, GB_2, mkulinski, ragreen, jackyalcine, Pitel, iodelay, bwowk, ZrenBot, ngraham, alexeymin, lesliezhai, ali-mohamed, hardening, jensreuterberg, abetts, sebas, apol, mart