Add minimize and maximize features on window frame

Add a condition in twin_window_dispatch() to handle clicks on the
minimize and maximize buttons located on the window frame. The
positions of these buttons are calculated for click detection.

A minimized window is considered inactive, even if it remains on top of
the screen. The window's title bar is blue only when the window is both
the topmost and active.

Signed-off-by: Wei-Hsin Yeh <weihsinyeh168@gmail.com>

Author: weihsinyeh

include/twin.h

@@ -443,6 +443,7 @@ struct _twin_window {
     twin_rect_t client;
     twin_rect_t damage;
     bool active;
+    bool minimize;
     bool client_grab;
     bool want_focus;
     bool draw_queued;

src/screen.c

@@ -9,6 +9,9 @@
 
 #include "twin_private.h"
 
+#define TWIN_BW 0
+#define TWIN_TITLE_HEIGHT 20
+
 twin_screen_t *twin_screen_create(twin_coord_t width,
                                   twin_coord_t height,
                                   twin_put_begin_t put_begin,
@@ -135,6 +138,12 @@ static void twin_screen_span_pixmap(twin_screen_t maybe_unused *screen,
         return;
     if (p->y + p->height <= y)
         return;
+
+    /* Skip drawing the window's client area if the window is minimized. */
+    if (p->window->minimize &&
+        y >= p->y + TWIN_BW + TWIN_TITLE_HEIGHT + TWIN_BW)
+        return;
+
     /* bounds check in x */
     p_left = left;
     if (p_left < p->x)

src/window.c

@@ -36,6 +36,7 @@ twin_window_t *twin_window_create(twin_screen_t *screen,
     window->screen = screen;
     window->style = style;
     window->active = false;
+    window->minimize = false;
     switch (window->style) {
     case TwinWindowApplication:
         left = TWIN_BW;
@@ -179,6 +180,9 @@ bool twin_window_valid_range(twin_window_t *window,
             y < window->pixmap->y + window->pixmap->height - offset_y) {
             if (y < window->pixmap->y + (window->client.top))
                 return !twin_pixmap_transparent(window->pixmap, x, y);
+            else
+                return !window->minimize;
+
             return true;
         }
         return false;
@@ -494,22 +498,67 @@ bool twin_window_dispatch(twin_window_t *window, twin_event_t *event)
     twin_event_t ev = *event;
     bool delegate = true;
 
+    twin_fixed_t bw = twin_int_to_fixed(TWIN_TITLE_BW);
+    twin_fixed_t t_h = twin_int_to_fixed(window->client.top) - bw;
+    twin_fixed_t t_arc_2 = t_h * 2 / 3;
+    twin_fixed_t c_right = twin_int_to_fixed(window->client.right) - bw / 2;
+    twin_fixed_t name_height = t_h - bw - bw / 2;
+    twin_fixed_t icon_size = name_height * 8 / 10;
+    twin_fixed_t menu_x = t_arc_2;
+    twin_fixed_t text_x = menu_x + icon_size + bw;
+    twin_fixed_t text_width;
+    twin_fixed_t title_right;
+    twin_path_t *path = twin_path_create();
+    const char *name = window->name;
+
+    text_width = twin_width_utf8(path, name);
+    twin_path_destroy(path);
+    title_right = (text_x + text_width + bw + icon_size + bw + icon_size + bw +
+                   icon_size + t_arc_2);
+
+    if (title_right < c_right)
+        c_right = title_right;
+
+    twin_fixed_t close_x = c_right - t_arc_2 - icon_size;
+    twin_fixed_t max_x = close_x - bw - icon_size;
+    twin_fixed_t min_x = max_x - bw - icon_size;
+    int local_x, local_y;
+
     switch (ev.kind) {
     case TwinEventButtonDown:
+        local_y = ev.u.pointer.screen_y - window->pixmap->y;
+        if (local_y >= 0 && local_y <= TWIN_BW + TWIN_TITLE_HEIGHT + TWIN_BW) {
+            local_x = ev.u.pointer.screen_x - window->pixmap->x;
+            if (local_x > twin_fixed_to_int(min_x) &&
+                local_x < twin_fixed_to_int(max_x)) {
+                window->minimize = true;
+                twin_pixmap_damage(window->pixmap, 0, 0, window->pixmap->width,
+                                   window->pixmap->height);
+            } else if (local_x > twin_fixed_to_int(max_x) &&
+                       local_x < twin_fixed_to_int(close_x)) {
+                window->minimize = false;
+                twin_pixmap_damage(window->pixmap, 0, 0, window->pixmap->width,
+                                   window->pixmap->height);
+            }
+        }
     case TwinEventActivate:
         /* Set window active. */
         /*
-         * When the box is trigger by TwinEventButtonDown, its window's title
-         * bar needs to change color and be put onto the toppest layer.
+         * If the window is minimized, it is not active. When the box is
+         * triggered by TwinEventButtonDown and the window is not minimized, the
+         * window's title bar should change to blue to indicate that it is on
+         * top of the screen and active.
          */
-        if (!window->active) {
+        if (window->minimize)
+            window->active = false;
+        else
             window->active = true;
-            twin_window_frame(window);
-            if (window != window->screen->top->window) {
-                window->screen->top->window->active = false;
-                twin_window_frame(window->screen->top->window);
-            }
+        twin_window_frame(window);
+        if (window != window->screen->top->window) {
+            window->screen->top->window->active = false;
+            twin_window_frame(window->screen->top->window);
         }
+
 #if defined(CONFIG_DROP_SHADOW)
         /* Handle drop shadow. */
         twin_window_drop_shadow(window);