shithub: choc

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textscreen: Fix rendering when using a tiling WM.

When using a tiling window manager, the window dimensions as passed
to SDL_CreateWindow() can potentially be ignored, and we can end up
with a different window size even though we didn't ask for the window
to be resizeable.

In this situation, we were scaling the textscreen image to always fill
the window, regardless of size or aspect ratio. This led to some nasty
looking, distorted views in some cases. Instead, always render the
textscreen image at the intended size and center the image within the
window if it is not the requested size.

--- a/textscreen/txt_sdl.c

+++ b/textscreen/txt_sdl.c

@@ -55,6 +55,10 @@

 static SDL_Renderer *renderer;

 static int key_mapping = 1;

+// Dimensions of the screen image in screen coordinates (not pixels); this

+// is the value that was passed to SDL_CreateWindow().

+static int screen_image_w, screen_image_h;

+

 static TxtSDLEventCallbackFunc event_callback;

 static void *event_callback_data;

@@ -244,7 +248,6 @@

 int TXT_Init(void)

 {

-    int window_w, window_h;

     int flags = 0;

     if (SDL_Init(SDL_INIT_VIDEO) < 0)

@@ -254,8 +257,8 @@

     ChooseFont();

-    window_w = TXT_SCREEN_W * font->w;

-    window_h = TXT_SCREEN_H * font->h;

+    screen_image_w = TXT_SCREEN_W * font->w;

+    screen_image_h = TXT_SCREEN_H * font->h;

     // If highdpi_font is selected, try to initialize high dpi rendering.

     if (font == &highdpi_font)

@@ -265,7 +268,7 @@

     TXT_SDLWindow =

         SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,

-                         window_w, window_h, flags);

+                         screen_image_w, screen_image_h, flags);

     if (TXT_SDLWindow == NULL)

         return 0;

@@ -281,10 +284,13 @@

         int render_w, render_h;

         if (SDL_GetRendererOutputSize(renderer, &render_w, &render_h) == 0

-         && render_w == TXT_SCREEN_W * large_font.w

-         && render_h == TXT_SCREEN_H * large_font.h)

+         && render_w >= TXT_SCREEN_W * large_font.w

+         && render_h >= TXT_SCREEN_H * large_font.h)

         {

             font = &large_font;

+            // Note that we deliberately do not update screen_image_{w,h}

+            // since these are the dimensions of textscreen image in screen

+            // coordinates, not pixels.

         }

     }

@@ -411,6 +417,17 @@

     }

 }

+static void GetDestRect(SDL_Rect *rect)

+{

+    int w, h;

+

+    SDL_GetRendererOutputSize(renderer, &w, &h);

+    rect->x = (w - screenbuffer->w) / 2;

+    rect->y = (h - screenbuffer->h) / 2;

+    rect->w = screenbuffer->w;

+    rect->h = screenbuffer->h;

+}

+

 void TXT_UpdateScreenArea(int x, int y, int w, int h)

 {

     SDL_Texture *screentx;

@@ -434,11 +451,6 @@

         }

     }

-    rect.x = x * font->w;

-    rect.y = y * font->h;

-    rect.w = (x_end - x) * font->w;

-    rect.h = (y_end - y) * font->h;

-

     SDL_UnlockSurface(screenbuffer);

     SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");

@@ -448,7 +460,8 @@

     screentx = SDL_CreateTextureFromSurface(renderer, screenbuffer);

     SDL_RenderClear(renderer);

-    SDL_RenderCopy(renderer, screentx, NULL, NULL);

+    GetDestRect(&rect);

+    SDL_RenderCopy(renderer, screentx, NULL, &rect);

     SDL_RenderPresent(renderer);

     SDL_DestroyTexture(screentx);

@@ -462,15 +475,36 @@

 void TXT_GetMousePosition(int *x, int *y)

 {

     int window_w, window_h;

+    int origin_x, origin_y;

     SDL_GetMouseState(x, y);

     // Translate mouse position from 'pixel' position into character position.

-    // Note that font->{w,h} are deliberately not used in this calculation, as

-    // that would break when using highdpi (OS X retina display).

+    // We are working here in screen coordinates and not pixels, since this is

+    // what SDL_GetWindowSize() returns; we must calculate and subtract the

+    // origin position since we center the image within the window.

     SDL_GetWindowSize(TXT_SDLWindow, &window_w, &window_h);

-    *x = (*x * TXT_SCREEN_W) / window_w;

-    *y = (*y * TXT_SCREEN_H) / window_h;

+    origin_x = (window_w - screen_image_w) / 2;

+    origin_y = (window_h - screen_image_h) / 2;

+    *x = ((*x - origin_x) * TXT_SCREEN_W) / screen_image_w;

+    *y = ((*y - origin_y) * TXT_SCREEN_H) / screen_image_h;

+

+    if (*x < 0)

+    {

+        *x = 0;

+    }

+    else if (*x >= TXT_SCREEN_W)

+    {

+        *x = TXT_SCREEN_W - 1;

+    }

+    if (*y < 0)

+    {

+        *y = 0;

+    }

+    else if (*y >= TXT_SCREEN_H)

+    {

+        *y = TXT_SCREEN_H - 1;

+    }

 }

 //