Add an option to emulate middle mouse with Alt

Useful for laptop with touchpad.

src/gesture.c

@@ -23,13 +23,30 @@
 // XXX: this value should be set depending on the screen resolution.
 static float g_start_dist = 8;
 
+static int g_emulate_three_buttons_mouse = 0;
+
+void gesture_set_emulate_three_buttons_mouse(int key)
+{
+    g_emulate_three_buttons_mouse = key;
+}
+
 static bool test_button(const inputs_t *inputs, const touch_t *touch, int mask)
 {
+    bool lmb = touch->down[0];
+    bool mmb = touch->down[1];
+    bool rmb = touch->down[2];
+
+    if (g_emulate_three_buttons_mouse &&
+        inputs->keys[g_emulate_three_buttons_mouse]) {
+        mmb = lmb;
+        lmb = false;
+    }
+
     if (mask & GESTURE_SHIFT && !inputs->keys[KEY_LEFT_SHIFT]) return false;
     if (mask & GESTURE_CTRL && !inputs->keys[KEY_CONTROL]) return false;
-    if ((mask & GESTURE_LMB) && !touch->down[0]) return false;
-    if ((mask & GESTURE_MMB) && !touch->down[1]) return false;
-    if ((mask & GESTURE_RMB) && !touch->down[2]) return false;
+    if ((mask & GESTURE_LMB) && !lmb) return false;
+    if ((mask & GESTURE_MMB) && !mmb) return false;
+    if ((mask & GESTURE_RMB) && !rmb) return false;
     return true;
 }
 

src/gesture.h

@@ -110,3 +110,9 @@ struct gesture
 int gesture_update(int nb, gesture_t *gestures[],
                    const inputs_t *inputs, const float viewport[4],
                    void *user);
+
+/*
+ * Set the key used to emulate middle mouse buttons with left click
+ * Set to zero to disable.
+ */
+void gesture_set_emulate_three_buttons_mouse(int key);

src/goxel.h

@@ -552,6 +552,9 @@ typedef struct goxel
     // Arr array of keymap settings (different from shortcuts).
     keymap_t *keymaps;
 
+    // Can be set to a key code (only KEY_LEFT_ALT is supported for now).
+    int emulate_three_buttons_mouse;
+
 } goxel_t;
 
 // the global goxel instance.

src/gui/settings.c

@@ -124,6 +124,7 @@ int gui_settings_popup(void *data)
     int ret = 0;
     const tr_lang_t *language;
     const tr_lang_t *languages;
+    bool val;
 
     if (gui_section_begin(_(LANGUAGE), GUI_SECTION_COLLAPSABLE)) {
         language = tr_get_language();
@@ -155,6 +156,16 @@ int gui_settings_popup(void *data)
         }
     } gui_section_end();
 
+    if (gui_section_begin("Inputs", GUI_SECTION_COLLAPSABLE_CLOSED)) {
+        val = goxel.emulate_three_buttons_mouse == KEY_LEFT_ALT;
+        if (gui_checkbox("Emulate 3 buttons with Alt", &val,
+                         "Emulate Middle Mouse with Alt+Left Mouse.")) {
+            goxel.emulate_three_buttons_mouse = val ? KEY_LEFT_ALT : 0;
+            gesture_set_emulate_three_buttons_mouse(
+                    goxel.emulate_three_buttons_mouse);
+            settings_save();
+        }
+    } gui_section_end();
 
     if (gui_section_begin(_(PATHS), GUI_SECTION_COLLAPSABLE_CLOSED)) {
         gui_text("Palettes: %s/palettes", sys_get_user_dir());
@@ -238,6 +249,13 @@ static int settings_ini_handler(void *user, const char *section,
     if (strcmp(section, "keymaps") == 0) {
         add_keymap(name, value);
     }
+    if (strcmp(section, "inputs") == 0) {
+        if (strcmp(name, "emulate_three_buttons_mouse") == 0) {
+            if (strcmp(value, "alt") == 0) {
+                goxel.emulate_three_buttons_mouse = KEY_LEFT_ALT;
+            }
+        }
+    }
     return 0;
 }
 
@@ -247,8 +265,10 @@ void settings_load(void)
     snprintf(path, sizeof(path), "%s/settings.ini", sys_get_user_dir());
     LOG_I("Read settings file: %s", path);
     arrfree(goxel.keymaps);
+    goxel.emulate_three_buttons_mouse = 0;
     ini_parse(path, settings_ini_handler, NULL);
     actions_check_shortcuts();
+    gesture_set_emulate_three_buttons_mouse(goxel.emulate_three_buttons_mouse);
 }
 
 static int shortcut_save_callback(action_t *a, void *user)
@@ -318,6 +338,12 @@ void settings_save(void)
     fprintf(file, "[shortcuts]\n");
     actions_iter(shortcut_save_callback, file);
 
+    if (goxel.emulate_three_buttons_mouse) {
+        assert(goxel.emulate_three_buttons_mouse == KEY_LEFT_ALT);
+        fprintf(file, "[inputs]\n");
+        fprintf(file, "emulate_three_buttons_mouse=alt");
+    }
+
     fprintf(file, "\n");
     save_keymaps(file);
     fprintf(file, "\n");

src/inputs.h

@@ -40,6 +40,7 @@ enum {
     KEY_LEFT_SHIFT  = 340,
     KEY_RIGHT_SHIFT = 344,
     KEY_CONTROL     = 341,
+    KEY_LEFT_ALT    = 342,
 };