From 05bd225a80556412cff052d74a72c5bf8333e403 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Tue, 26 Apr 2022 23:14:44 -0400
Subject: [PATCH] x11: If XRandR isn't available, add a generic display.
We can get _some_ of the info we need out of standard Xlib and report a
single display (which might actually be multiple physical displays mushed
into a single desktop). This is better than nothing, but you should really
just build with XRandR support and get a better X server. :)
---
src/video/x11/SDL_x11modes.c | 152 ++++++++++++++++++++++++++++-------
1 file changed, 122 insertions(+), 30 deletions(-)
diff --git a/src/video/x11/SDL_x11modes.c b/src/video/x11/SDL_x11modes.c
index 354baa39dd1..87d99541c18 100644
--- a/src/video/x11/SDL_x11modes.c
+++ b/src/video/x11/SDL_x11modes.c
@@ -148,6 +148,30 @@ X11_GetPixelFormatFromVisualInfo(Display * display, XVisualInfo * vinfo)
return SDL_PIXELFORMAT_UNKNOWN;
}
+static int
+GetXftDPI(Display* dpy)
+{
+ char* xdefault_resource;
+ int xft_dpi, err;
+
+ xdefault_resource = X11_XGetDefault(dpy, "Xft", "dpi");
+
+ if(!xdefault_resource) {
+ return 0;
+ }
+
+ /*
+ * It's possible for SDL_atoi to call SDL_strtol, if it fails due to a
+ * overflow or an underflow, it will return LONG_MAX or LONG_MIN and set
+ * errno to ERANGE. So we need to check for this so we dont get crazy dpi
+ * values
+ */
+ xft_dpi = SDL_atoi(xdefault_resource);
+ err = errno;
+
+ return err == ERANGE ? 0 : xft_dpi;
+}
+
#if SDL_VIDEO_DRIVER_X11_XRANDR
static SDL_bool
CheckXRandR(Display * display, int *major, int *minor)
@@ -289,30 +313,6 @@ SetXRandRDisplayName(Display *dpy, Atom EDID, char *name, const size_t namelen,
#endif
}
-static int
-GetXftDPI(Display* dpy)
-{
- char* xdefault_resource;
- int xft_dpi, err;
-
- xdefault_resource = X11_XGetDefault(dpy, "Xft", "dpi");
-
- if(!xdefault_resource) {
- return 0;
- }
-
- /*
- * It's possible for SDL_atoi to call SDL_strtol, if it fails due to a
- * overflow or an underflow, it will return LONG_MAX or LONG_MIN and set
- * errno to ERANGE. So we need to check for this so we dont get crazy dpi
- * values
- */
- xft_dpi = SDL_atoi(xdefault_resource);
- err = errno;
-
- return err == ERANGE ? 0 : xft_dpi;
-}
-
static int
X11_InitModes_XRandR(_THIS)
{
@@ -478,16 +478,107 @@ X11_InitModes_XRandR(_THIS)
}
#endif /* SDL_VIDEO_DRIVER_X11_XRANDR */
-int
-X11_InitModes(_THIS)
+/* This is used if there's no better functionality--like XRandR--to use.
+ It won't attempt to supply different display modes at all, but it can
+ enumerate the current displays and their current sizes. */
+static int X11_InitModes_StdXlib(_THIS)
{
+ /* !!! FIXME: a lot of copy/paste from X11_InitModes_XRandR in this function. */
SDL_VideoData *data = (SDL_VideoData *) _this->driverdata;
+ Display *dpy = data->display;
+ const int default_screen = DefaultScreen(dpy);
+ Screen *screen = ScreenOfDisplay(dpy, default_screen);
+ int display_mm_width, display_mm_height, xft_dpi, scanline_pad, n, i;
+ SDL_DisplayModeData *modedata;
+ SDL_DisplayData *displaydata;
+ SDL_DisplayMode mode;
+ XPixmapFormatValues *pixmapformats;
+ Uint32 pixelformat;
+ XVisualInfo vinfo;
+ SDL_VideoDisplay display;
+
+ /* note that generally even if you have a multiple physical monitors, ScreenCount(dpy) still only reports ONE screen. */
+
+ if (get_visualinfo(dpy, default_screen, &vinfo) < 0) {
+ return SDL_SetError("Failed to find an X11 visual for the primary display");
+ }
+
+ pixelformat = X11_GetPixelFormatFromVisualInfo(dpy, &vinfo);
+ if (SDL_ISPIXELFORMAT_INDEXED(pixelformat)) {
+ return SDL_SetError("Palettized video modes are no longer supported");
+ }
-/* XRandR is the One True Modern Way to do this on X11. If this
- fails, we just won't report any display modes except the current
- desktop size. */
+ SDL_zero(mode);
+ mode.w = WidthOfScreen(screen);
+ mode.h = HeightOfScreen(screen);
+ mode.format = pixelformat;
+ mode.refresh_rate = 0; /* don't know it, sorry. */
+
+ displaydata = (SDL_DisplayData *) SDL_calloc(1, sizeof(*displaydata));
+ if (!displaydata) {
+ return SDL_OutOfMemory();
+ }
+
+ modedata = (SDL_DisplayModeData *) SDL_calloc(1, sizeof(SDL_DisplayModeData));
+ if (!modedata) {
+ SDL_free(displaydata);
+ return SDL_OutOfMemory();
+ }
+ mode.driverdata = modedata;
+
+ display_mm_width = WidthMMOfScreen(screen);
+ display_mm_height = HeightMMOfScreen(screen);
+
+ displaydata->screen = default_screen;
+ displaydata->visual = vinfo.visual;
+ displaydata->depth = vinfo.depth;
+ displaydata->hdpi = display_mm_width ? (((float) mode.w) * 25.4f / display_mm_width) : 0.0f;
+ displaydata->vdpi = display_mm_height ? (((float) mode.h) * 25.4f / display_mm_height) : 0.0f;
+ displaydata->ddpi = SDL_ComputeDiagonalDPI(mode.w, mode.h, ((float) display_mm_width) / 25.4f,((float) display_mm_height) / 25.4f);
+
+ xft_dpi = GetXftDPI(dpy);
+ if(xft_dpi > 0) {
+ displaydata->hdpi = (float)xft_dpi;
+ displaydata->vdpi = (float)xft_dpi;
+ }
+
+ scanline_pad = SDL_BYTESPERPIXEL(pixelformat) * 8;
+ pixmapformats = X11_XListPixmapFormats(dpy, &n);
+ if (pixmapformats) {
+ for (i = 0; i < n; ++i) {
+ if (pixmapformats[i].depth == vinfo.depth) {
+ scanline_pad = pixmapformats[i].scanline_pad;
+ break;
+ }
+ }
+ X11_XFree(pixmapformats);
+ }
+
+ displaydata->scanline_pad = scanline_pad;
+ displaydata->x = 0;
+ displaydata->y = 0;
+ displaydata->use_xrandr = SDL_FALSE;
+
+ SDL_zero(display);
+ display.name = (char *) "Generic X11 Display"; /* this is just copied and thrown away, it's safe to cast to char* here. */
+ display.desktop_mode = mode;
+ display.current_mode = mode;
+ display.driverdata = displaydata;
+ SDL_AddVideoDisplay(&display, SDL_FALSE);
+
+ return 0;
+}
+
+
+int
+X11_InitModes(_THIS)
+{
+ /* XRandR is the One True Modern Way to do this on X11. If this
+ fails, we just won't report any display modes except the current
+ desktop size. */
#if SDL_VIDEO_DRIVER_X11_XRANDR
{
+ SDL_VideoData *data = (SDL_VideoData *) _this->driverdata;
int xrandr_major, xrandr_minor;
/* require at least XRandR v1.3 */
if (CheckXRandR(data->display, &xrandr_major, &xrandr_minor) &&
@@ -497,7 +588,8 @@ X11_InitModes(_THIS)
}
#endif /* SDL_VIDEO_DRIVER_X11_XRANDR */
- return 0;
+ /* still here? Just set up an extremely basic display. */
+ return X11_InitModes_StdXlib(_this);
}
void