From e80e45eaa6015f82d05f8f3af725bd95c110c35d Mon Sep 17 00:00:00 2001
From: Wei-Hsin Yeh <weihsinyeh168@gmail.com>
Date: Fri, 24 Jan 2025 19:03:35 +0800
Subject: [PATCH] Fix active window not working on the framebuffer

Remove the inefficiently function twin_active_pixmap(). This function
finds the currently and previously active window pixel map by traversing
the list of pixel maps. This function will be called every time the
screen needs to be updated. Set the active variable of the window only
when the window's event TwinEventButtonDown is triggered to avoid
redundant operations.

Close #92

Signed-off-by: Wei-Hsin Yeh <weihsinyeh168@gmail.com>
---
 apps/main.c  |  1 +
 src/screen.c | 39 +--------------------------------------
 src/window.c | 14 ++++++++++++++
 3 files changed, 16 insertions(+), 38 deletions(-)

diff --git a/apps/main.c b/apps/main.c
index db3a33c..f746704 100644
--- a/apps/main.c
+++ b/apps/main.c
@@ -132,6 +132,7 @@ int main(void)
     apps_image_start(tx->screen, "Viewer", 20, 20);
 #endif
 
+    twin_screen_set_active(tx->screen, tx->screen->top);
     twin_dispatch(tx);
 
     return 0;
diff --git a/src/screen.c b/src/screen.c
index c3dfb2d..76bcfe2 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -151,25 +151,6 @@ static void twin_screen_span_pixmap(twin_screen_t maybe_unused *screen,
         op32(dst, src, p_right - p_left);
 }
 
-static twin_pixmap_t *twin_active_pixmap(twin_screen_t *screen,
-                                         twin_pixmap_t **active_pix)
-{
-    twin_pixmap_t *p = NULL, *prev_active_pix = NULL;
-    /*
-     * Identify the previously active pixel map and the currently active pixel
-     * map, which is on the topmost layer.
-     */
-    for (p = screen->bottom; p; p = p->up) {
-        if (p->window->active == true) {
-            prev_active_pix = p;
-            prev_active_pix->window->active = false;
-        }
-        (*active_pix) = p;
-    }
-    (*active_pix)->window->active = true;
-    return prev_active_pix;
-}
-
 void twin_screen_update(twin_screen_t *screen)
 {
     twin_coord_t left = screen->damage.left;
@@ -189,7 +170,7 @@ void twin_screen_update(twin_screen_t *screen)
 
     if (!screen->disable && left < right && top < bottom) {
         twin_argb32_t *span;
-        twin_pixmap_t *p, *active_pix = NULL, *prev_active_pix = NULL;
+        twin_pixmap_t *p;
         twin_coord_t y;
         twin_coord_t width = right - left;
 
@@ -202,24 +183,6 @@ void twin_screen_update(twin_screen_t *screen)
 
         if (screen->put_begin)
             (*screen->put_begin)(left, top, right, bottom, screen->closure);
-
-        prev_active_pix = twin_active_pixmap(screen, &active_pix);
-
-        /*
-         * Mark the previously active pixel map as damaged to update its
-         * changes.
-         */
-        if (prev_active_pix && active_pix != prev_active_pix) {
-            twin_pixmap_damage(prev_active_pix, 0, 0, prev_active_pix->width,
-                               prev_active_pix->height);
-            twin_window_draw(prev_active_pix->window);
-        }
-
-        /* Mark the active pixel map as damaged to update its changes. */
-        twin_pixmap_damage(active_pix, 0, 0, active_pix->width,
-                           active_pix->height);
-        twin_window_draw(active_pix->window);
-
         for (y = top; y < bottom; y++) {
             if (screen->background) {
                 twin_pointer_t dst;
diff --git a/src/window.c b/src/window.c
index 59696fd..3e2547a 100644
--- a/src/window.c
+++ b/src/window.c
@@ -387,6 +387,20 @@ bool twin_window_dispatch(twin_window_t *window, twin_event_t *event)
 
     switch (ev.kind) {
     case TwinEventButtonDown:
+    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 (!window->active) {
+            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);
+            }
+        }
         if (window->client.left <= ev.u.pointer.x &&
             ev.u.pointer.x < window->client.right &&
             window->client.top <= ev.u.pointer.y &&