Hi,
On Tue, 2025-05-13 at 00:37 +0000, Kim, Dongwon wrote:
> Hi,
>
> > Subject: [PATCH 8/9] ui/gtk-gl-area: Render guest content with
> > padding in
> > fixed-scale mode
> >
> > In fixed-scale mode (zoom-to-fit=false), we expect that scale
> > should not
> > change, meaning that if window size is larger than guest surface,
> > padding is
>
> # @zoom-to-fit: Zoom guest display to fit into the host window. When
> # turned off the host window will be resized instead. In case
> the
> # display device can notify the guest on window resizes
> # (virtio-gpu) this will default to "on", assuming the guest will
> # resize the display to match the window size then. Otherwise it
> # defaults to "off". (Since 3.1)
>
> Current definition says the host window should be resized to fit the
> size of the guest surface instead. Wouldn't padding accommodate this?
>
Yeah, window will be resized to fit the size of guest surface in fixed-
scale mode. However, users are still allowed to resize the window to a
larger size and this is case where padding is required, otherwise the
fixed-scale assumption is broken. In fact, gl=off mode employs padding
to preserve scale already but gl=on mode doesn't follow this behavior,
which, IMO, is a defect that this patch is trying to correct.
Best regards,
Weifeng
> > supposed to be added to preserve the scale. However, in OpenGL mode
> > (gl=on), guest surface is always painted to the whole canvas
> > without any
> > padding. This change tries to fix this bug by adding appropriate
> > padding
> > when drawing surfaces.
> >
> > Signed-off-by: Weifeng Liu <weifeng.li...@gmail.com>
> > ---
> > ui/gtk-gl-area.c | 33 ++++++++++++++++++++++++++++++++-
> > 1 file changed, 32 insertions(+), 1 deletion(-)
> >
> > diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c index
> > db93cd6204..8151cc413c
> > 100644
> > --- a/ui/gtk-gl-area.c
> > +++ b/ui/gtk-gl-area.c
> > @@ -44,7 +44,9 @@ void gd_gl_area_draw(VirtualConsole *vc) #endif
> > int pw, ph, gs, y1, y2;
> > int ww, wh;
> > + int ww_surface, wh_surface;
> > int fbw, fbh;
> > + int wx_offset, wy_offset;
> >
> > if (!vc->gfx.gls) {
> > return;
> > @@ -61,6 +63,17 @@ void gd_gl_area_draw(VirtualConsole *vc)
> >
> > gd_update_scale(vc, ww, wh, fbw, fbh);
> >
> > + ww_surface = fbw * vc->gfx.scale_x;
> > + wh_surface = fbh * vc->gfx.scale_y;
> > +
> > + wx_offset = wy_offset = 0;
> > + if (ww > ww_surface) {
> > + wx_offset = (ww - ww_surface) / 2;
> > + }
> > + if (wh > wh_surface) {
> > + wy_offset = (wh - wh_surface) / 2;
> > + }
> > +
> > if (vc->gfx.scanout_mode) {
> > if (!vc->gfx.guest_fb.framebuffer) {
> > return;
> > @@ -79,11 +92,29 @@ void gd_gl_area_draw(VirtualConsole *vc)
> > glBindFramebuffer(GL_READ_FRAMEBUFFER, vc-
> > > gfx.guest_fb.framebuffer);
> > /* GtkGLArea sets GL_DRAW_FRAMEBUFFER for us */
> >
> > + if (wx_offset > 0) {
> > + glEnable(GL_SCISSOR_TEST);
> > + glScissor(0, 0, wx_offset * gs, wh * gs);
> > + glClear(GL_COLOR_BUFFER_BIT);
> > + glScissor((ww - wx_offset) * gs, 0, wx_offset * gs, wh
> > * gs);
> > + glClear(GL_COLOR_BUFFER_BIT);
> > + glDisable(GL_SCISSOR_TEST);
> > + }
> > + if (wy_offset > 0) {
> > + glEnable(GL_SCISSOR_TEST);
> > + glScissor(0, 0, ww * gs, wy_offset * gs);
> > + glClear(GL_COLOR_BUFFER_BIT);
> > + glScissor(0, (wh - wy_offset) * gs, ww * gs, wy_offset
> > * gs);
> > + glClear(GL_COLOR_BUFFER_BIT);
> > + glDisable(GL_SCISSOR_TEST);
> > + }
> > +
> > glViewport(0, 0, pw, ph);
> > y1 = vc->gfx.y0_top ? 0 : vc->gfx.h;
> > y2 = vc->gfx.y0_top ? vc->gfx.h : 0;
> > glBlitFramebuffer(0, y1, vc->gfx.w, y2,
> > - 0, 0, pw, ph,
> > + wx_offset * gs, wy_offset * gs,
> > + (ww - wx_offset) * gs, (wh - wy_offset)
> > * gs,
> > GL_COLOR_BUFFER_BIT, GL_NEAREST);
> > #ifdef CONFIG_GBM
> > if (dmabuf) {
> > --
> > 2.49.0
> >
>
> Thanks
