Fixes bug with viewport not updating when moving window between monitors with different scale
factors on Windows (this should also fix the same issue on other OS'es, though untested)
Adds hint "SDL_WINDOWS_DPI_SCALING" which can be set to "1" to
change the SDL coordinate system units to be DPI-scaled points, rather
than pixels everywhere.
This means windows will be appropriately sized, even when created on
high-DPI displays with scaling.
e.g. requesting a 640x480 window from SDL, on a display with 125%
scaling in Windows display settings, will create a window with an
800x600 client area (in pixels).
Setting this to "1" implicitly requests process DPI awareness
(setting SDL_WINDOWS_DPI_AWARENESS is unnecessary),
and forces SDL_WINDOW_ALLOW_HIGHDPI on all windows.
If the move results in a DPI change, we need to allow the window to resize (e.g. AdjustWindowRectExForDpi frame sizes are different).
- WM_DPICHANGED: Don't assume WM_GETDPISCALEDSIZE is always called for PMv2 awareness - it's only called during interactive dragging.
- WIN_AdjustWindowRectWithStyle: always calculate final window size including frame based on the destination rect,
not based on the current window DPI.
- Update wmmsg.h to include WM_GETDPISCALEDSIZE (for WMMSG_DEBUG)
- WIN_AdjustWindowRectWithStyle: add optional logging
- WM_GETMINMAXINFO: add optional HIGHDPI_DEBUG logging
- WM_DPICHANGED: fix potentially clobbering data->expected_resize
Together these changes fix the following scenario:
- launch testwm2 with the SDL_WINDOWS_DPI_AWARENESS=permonitorv2 environment variable
- Windows 10 21H2 (OS Build 19044.1706)
- Left (primary) monitor: 3840x2160, 125% scaling
- Right (secondary) monitor: 2560x1440, 100% scaling
- Alt+Enter, Alt+Enter (to enter + leave desktop fullscreen), Alt+Right (to move window to right monitor). Ensure the window client area stays 640x480. Drag the window back to the 125% monitor, ensure client area stays 640x480.
The hint allows setting a specific DPI awareness ("unaware", "system", "permonitor", "permonitorv2").
This is the first part of High-DPI support on Windows ( https://github.com/libsdl-org/SDL/issues/2119 ).
It doesn't implement a virtualized SDL coordinate system, which will be
addressed in a later commit. (This hint could be useful for SDL apps
that want 1 SDL unit = 1 pixel, though.)
Detecting and behaving correctly under per-monitor V2
(calling AdjustWindowRectExForDpi where needed) should fix the
following issues:
https://github.com/libsdl-org/SDL/issues/3286https://github.com/libsdl-org/SDL/issues/4712
* SDLTest_CommonDrawWindowInfo: log SDL_RenderGetScale, SDL_RenderGetLogicalSize
* testwm2: fix video modes menu hit detection in High DPI cases
- also when logical size is specified, e.g.
`--logical 640x480 --resizable --allow-highdpi`
* add function to determine logical coordinates of renderer point when given window point
* change since to the targeted milestone
* fix typo
* rename for consistency
* Change logical coordinate type to float, since we can render with floating point precision.
* add function to convert logical to window coordinates
* testwm2: use new SDL_RenderWindowToLogical
* SDL_render.c: alternate SDL_RenderWindowToLogical/SDL_RenderLogicalToWindow
Co-authored-by: John Blat <johnblat64@protonmail.com>
Co-authored-by: John Blat <47202511+johnblat64@users.noreply.github.com>
Eric Wasylishen