shithub: puzzles

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js: Take device pixel ratio into account when setting default size

This is a bit of a hack.  When setting the puzzle to its default size,
either at startup or from a right-click on the resize handle, we now
scale the default size from midend_size() by the device pixel ratio,
and then pass that back to midend_size().  This does more or less the
right thing, in that the puzzle now starts up at a size that scales
with the font size.

There are still some slight inconsistencies, where sequences of DPR
changes and puzzle parameter changes can have order-dependent effects
on the size of the puzzle.  Happily these effects are small and fairly
hard to observe.

--- a/emcc.c

+++ b/emcc.c

@@ -83,6 +83,7 @@

 extern void js_canvas_set_statusbar(const char *text);

 extern void js_canvas_set_size(int w, int h);

 extern void js_canvas_set_nominal_size();

+extern double js_get_device_pixel_ratio();

 extern void js_dialog_init(const char *title);

 extern void js_dialog_string(int i, const char *title, const char *initvalue);

@@ -183,12 +184,32 @@

  */

 static int canvas_w, canvas_h;

-/* Called when we resize as a result of changing puzzle settings */

-static void resize(void)

+/* 

+ * Called when we resize as a result of changing puzzle settings.

+ * "initial" is true if this is the first call, or the first call

+ * since a midend_reset_tilesize().  In that case, we might want to

+ * adjust the size to compensate for the device pixel ratio.

+ */

+static void resize(bool initial)

 {

     int w, h;

+    double dpr;

     w = h = INT_MAX;

     midend_size(me, &w, &h, false);

+    if (initial) {

+        dpr = js_get_device_pixel_ratio();

+        if (dpr != 1.0) {

+            /*

+             * The default w and h are probably in units of

+             * sensible-sized pixels (~0.25 mm).  Scale them to the

+             * actual device pixels and then ask for a size near

+             * that.

+             */

+            w *= dpr;

+            h *= dpr;

+            midend_size(me, &w, &h, true);

+        }

+    }

     js_canvas_set_size(w, h);

     js_canvas_set_nominal_size();

     canvas_w = w;

@@ -218,7 +239,7 @@

 void restore_puzzle_size(int w, int h)

 {

     midend_reset_tilesize(me);

-    resize();

+    resize(true);

     midend_force_redraw(me);

 }

@@ -713,7 +734,7 @@

              */

             select_appropriate_preset();

             midend_new_game(me);

-            resize();

+            resize(false);

             midend_redraw(me);

             free_cfg(cfg);

             js_dialog_cleanup();

@@ -770,7 +791,7 @@

                 assert(i < npresets);

                 midend_set_params(me, presets[i]);

                 midend_new_game(me);

-                resize();

+                resize(false);

                 midend_redraw(me);

                 update_undo_redo();

                 js_focus_canvas();

@@ -894,7 +915,7 @@

         js_error_box(err);

     } else {

         select_appropriate_preset();

-        resize();

+        resize(false);

         midend_redraw(me);

         update_permalinks();

         update_undo_redo();

@@ -936,7 +957,7 @@

      * canvas size appropriately.

      */

     midend_new_game(me);

-    resize();

+    resize(true);

     /*

      * Create a status bar, if needed.

--- a/emcclib.js

+++ b/emcclib.js

@@ -570,6 +570,15 @@

     },

     /*

+     * double js_get_device_pixel_ratio();

+     *

+     * Return the current device pixel ratio.

+     */

+    js_get_device_pixel_ratio: function() {

+        return window.devicePixelRatio || 1;

+    },

+

+    /*

      * void js_dialog_init(const char *title);

      * 

      * Begin constructing a 'dialog box' which will be popped up in an