Merge branch 'dpi-aware-when-scaling-factor-is-one'

CHANGELOG.md

@@ -78,10 +78,13 @@ means foot can be PGO:d in e.g. sandboxed build scripts. See
 * **bold-text-in-bright** option to `foot.ini`. When enabled, bold
   text is rendered in a brighter color
   (https://codeberg.org/dnkl/foot/issues/199).
-* **dpi-aware** option to `foot.ini`. The default, **enabled**,
+* **dpi-aware** option to `foot.ini`. The default, `auto`, sizes fonts
-  implements foot's old font sizing behavior. But, when **disabled**,
+  using the monitor’s DPI when output scaling has been
-  foot will ignore the monitors' DPI and instead size fonts using the
+  **disabled**. If output scaling has been **enabled**, fonts are
-  scale factor alone (https://codeberg.org/dnkl/foot/issues/206).
+  sized using the scaling factor. DPI-only font sizing can be forced
+  by setting `dpi-aware=yes`. Setting `dpi-aware=no` forces font
+  sizing to be based on the scaling factor.
+  (https://codeberg.org/dnkl/foot/issues/206).
 * `-w,--window-size-pixels` and `-W,--window-size-chars` command line
   options to `footclient` (https://codeberg.org/dnkl/foot/issues/189).
 * Short command line options for `--title`, `--maximized`,

README.md

@@ -315,8 +315,12 @@ Foot will re-size the fonts on-the-fly when the window is moved
 between screens with different DPIs values. If the window covers
 multiple screens, with different DPIs, the highest DPI will be used.
 
-_Tip_: QT applications can be configured to work this way too, by
+Starting with foot-1.6, the _default_ behavior is to use the monitor’s
-exporting the environment variable `QT_WAYLAND_FORCE_DPI=physical`.
+DPI to size fonts when output scaling has been disabled. On monitors
+where output scaling has been enabled, fonts will instead be sized
+using the scaling factor. This can be changed with the `dpi-aware`
+option in `foot.ini`. See the man page, **foot.ini**(5) for more
+information.
 
 _Note_: if you configure **pixelsize**, rather than **size**, then DPI
 changes will **not** change the font size. Pixels are always pixels.

config.c

@@ -548,8 +548,12 @@ parse_section_main(const char *key, const char *value, struct config *conf,
         free(copy);
     }
 
-    else if (strcmp(key, "dpi-aware") == 0)
+    else if (strcmp(key, "dpi-aware") == 0) {
-        conf->dpi_aware = str_to_bool(value);
+        if (strcmp(value, "auto") == 0)
+            conf->dpi_aware = DPI_AWARE_AUTO;
+        else
+            conf->dpi_aware = str_to_bool(value) ? DPI_AWARE_YES : DPI_AWARE_NO;
+    }
 
     else if (strcmp(key, "workers") == 0) {
         unsigned long count;
@@ -1959,7 +1963,7 @@ config_load(struct config *conf, const char *conf_path,
         .bell_action = BELL_ACTION_NONE,
         .startup_mode = STARTUP_WINDOWED,
         .fonts = {tll_init(), tll_init(), tll_init(), tll_init()},
-        .dpi_aware = true,  /* Use DPI by default, not scale factor */
+        .dpi_aware = DPI_AWARE_AUTO, /* DPI-aware when scaling-factor == 1 */
         .scrollback = {
             .lines = 1000,
             .indicator = {

config.h

@@ -80,7 +80,7 @@ struct config {
 
     enum { STARTUP_WINDOWED, STARTUP_MAXIMIZED, STARTUP_FULLSCREEN } startup_mode;
 
-    bool dpi_aware;
+    enum {DPI_AWARE_AUTO, DPI_AWARE_YES, DPI_AWARE_NO} dpi_aware;
     config_font_list_t fonts[4];
 
     struct {

doc/foot.ini.5.scd

@@ -44,19 +44,24 @@ in this order:
 	*font-italic*, *font-bold-italic*).
 
 *dpi-aware*
-	Boolean. When enabled, fonts are sized using the monitor's DPI,
+	*auto*, *yes*, or *no*. When set to *yes*, fonts are sized using
-	making a font of a given size have the same physical size,
+	the monitor's DPI, making a font of a given size have the same
-	regardless of monitor. In other words, if you drag a foot window
+	physical size, regardless of monitor. In other words, if you drag
-	between different monitors, the font size remains the same.
+	a foot window between different monitors, the font size remains
+	the same.
 	
-	In this mode, the monitor's scale factor is ignored; doubling the
+	In this mode, the monitor's scaling factor is ignored; doubling
-	scale factor will *not* double the font size.
+	the scaling factor will *not* double the font size.
 	
-	When disabled, the monitor's DPI is ignored. The font is instead
+	When set to *no*, the monitor's DPI is ignored. The font is
-	sized using the monitor's scale factor; doubling the scale factor
+	instead sized using the monitor's scaling factor; doubling the
-	*does* double the font size.
+	scaling factor *does* double the font size.
-
+	
-	Default: _yes_
+	Finally, if set to *auto*, fonts will be sized using the monitor's
+	DPI on monitors with a scaling factor of 1, but otherwise size
+	fonts using the scaling factor.
+	
+	Default: _auto_
 
 *pad*
 	Padding between border and glyphs, in pixels (subject to output

terminal.c

@@ -776,6 +776,26 @@ get_font_subpixel(const struct terminal *term)
     return FCFT_SUBPIXEL_DEFAULT;
 }
 
+static bool
+font_should_size_by_dpi(const struct terminal *term, int new_scale)
+{
+    return term->conf->dpi_aware == DPI_AWARE_YES ||
+        (term->conf->dpi_aware == DPI_AWARE_AUTO && new_scale <= 1);
+}
+
+static bool
+font_size_by_dpi(const struct terminal *term)
+{
+    return font_should_size_by_dpi(term, term->font_scale);
+}
+
+static bool
+font_size_by_scale(const struct terminal *term)
+{
+    return !font_size_by_dpi(term);
+}
+
+
 struct font_load_data {
     size_t count;
     const char **names;
@@ -812,7 +832,7 @@ reload_fonts(struct terminal *term)
             bool use_px_size = term->font_sizes[i][j].px_size > 0;
             char size[64];
 
-            const int scale = term->conf->dpi_aware ? 1 : term->scale;
+            const int scale = font_size_by_scale(term) ? term->scale : 1;
 
             if (use_px_size)
                 snprintf(size, sizeof(size), ":pixelsize=%d",
@@ -843,12 +863,12 @@ reload_fonts(struct terminal *term)
     const char **names_bold = (const char **)(custom_bold ? names[1] : names[0]);
 
     const size_t count_italic = custom_italic ? counts[2] : counts[0];
-    const char **names_italic = (const char **)(custom_italic ? names[2] : names[0]); 
+    const char **names_italic = (const char **)(custom_italic ? names[2] : names[0]);
 
     const size_t count_bold_italic = custom_bold_italic ? counts[3] : counts[0];
     const char **names_bold_italic = (const char **)(custom_bold_italic ? names[3] : names[0]);
 
-    const bool use_dpi = term->conf->dpi_aware;
+    const bool use_dpi = font_size_by_dpi(term);
 
     char *attrs[4] = {NULL};
     int attr_len[4] = {-1, -1, -1, -1};  /* -1, so that +1 (below) results in 0 */
@@ -1673,23 +1693,34 @@ term_font_size_reset(struct terminal *term)
 bool
 term_font_dpi_changed(struct terminal *term)
 {
-    if (term->conf->dpi_aware) {
+    float dpi = get_font_dpi(term);
-        float dpi = get_font_dpi(term);
+    int scale = get_font_scale(term);
-        if (dpi == term->font_dpi)
-            return true;
 
-        LOG_DBG("DPI changed (%.2f -> %.2f): reloading fonts", term->font_dpi, dpi);
+    bool was_scaled_using_dpi = font_size_by_dpi(term);
-        term->font_dpi = dpi;
+    bool will_scale_using_dpi = font_should_size_by_dpi(term, scale);
-    } else {
-        int scale = get_font_scale(term);
-        if (scale == term->font_scale)
-            return true;
 
-        LOG_DBG("scale factor changed (%d -> %d): reloading fonts",
+    bool need_font_reload =
-                term->font_scale, scale);
+        was_scaled_using_dpi != will_scale_using_dpi ||
-        term->font_scale = scale;
+        (will_scale_using_dpi
+         ? term->font_dpi != dpi
+         : term->font_scale != scale);
+
+    if (need_font_reload) {
+        LOG_DBG("DPI/scale change: DPI-awareness=%s, "
+                "DPI: %.2f -> %.2f, scale: %d -> %d, "
+                "sizing font based on monitor's %s",
+                term->conf->dpi_aware == DPI_AWARE_AUTO ? "auto" :
+                term->conf->dpi_aware == DPI_AWARE_ON ? "yes" : "no",
+                term->font_dpi, dpi, term->font_scale, scale,
+                will_scale_using_dpi ? "DPI" : "scaling factor");
     }
 
+    term->font_dpi = dpi;
+    term->font_scale = scale;
+
+    if (!need_font_reload)
+        return true;
+
     return reload_fonts(term);
 }