feat: add animated focus transitions for window titles and taskbar colors

src/client.c

@@ -90,6 +90,7 @@ Client *client_create(Window window)
 
     client_update_title(client);
     client_update_class(client);
+    client->taskbar_color = generate_unique_color();
 
     return client;
 }
@@ -353,9 +354,12 @@ void client_focus(Client *client, bool update_mru)
     Window prev_window = None;
     if (ws != NULL && ws->focused != NULL && ws->focused != client) {
         prev_window = ws->focused->window;
+        client_start_focus_animation(ws->focused, false);
         client_unfocus(ws->focused);
     }
 
+    client_start_focus_animation(client, true);
+
     client_sync_log("client_focus: XSetInputFocus");
 
     XSetInputFocus(dwn->display, client->window, RevertToPointerRoot, CurrentTime);
@@ -1283,3 +1287,85 @@ Client *client_get_last(void)
     }
     return c;
 }
+
+
+#define FOCUS_ANIMATION_DURATION_MS 200
+
+void client_start_focus_animation(Client *client, bool gaining_focus)
+{
+    if (client == NULL) {
+        return;
+    }
+
+    unsigned long full_color = client->taskbar_color;
+    unsigned long dimmed_color = dim_color(client->taskbar_color, 0.6f);
+
+    if (gaining_focus) {
+        client->title_anim.from_color = dimmed_color;
+        client->title_anim.to_color = full_color;
+    } else {
+        client->title_anim.from_color = full_color;
+        client->title_anim.to_color = dimmed_color;
+    }
+
+    client->title_anim.start_time = get_time_ms();
+    client->title_anim.progress = 0.0f;
+    client->title_anim.active = true;
+}
+
+unsigned long client_get_animated_title_color(Client *client)
+{
+    if (client == NULL) {
+        return 0;
+    }
+
+    Workspace *ws = workspace_get(client->workspace);
+    bool is_focused = (ws != NULL && ws->focused == client);
+
+    if (client->title_anim.active) {
+        return interpolate_color(client->title_anim.from_color,
+                                 client->title_anim.to_color,
+                                 client->title_anim.progress);
+    }
+
+    if (is_focused) {
+        return client->taskbar_color;
+    }
+
+    return dim_color(client->taskbar_color, 0.6f);
+}
+
+void client_update_animations(void)
+{
+    if (dwn == NULL) {
+        return;
+    }
+
+    long now = get_time_ms();
+    bool needs_redraw = false;
+
+    for (Client *c = dwn->client_list; c != NULL; c = c->next) {
+        if (!c->title_anim.active) {
+            continue;
+        }
+
+        long elapsed = now - c->title_anim.start_time;
+        c->title_anim.progress = (float)elapsed / (float)FOCUS_ANIMATION_DURATION_MS;
+
+        if (c->title_anim.progress >= 1.0f) {
+            c->title_anim.progress = 1.0f;
+            c->title_anim.active = false;
+        }
+
+        if (c->frame != None && c->workspace == (unsigned int)dwn->current_workspace) {
+            Workspace *ws = workspace_get(c->workspace);
+            bool focused = (ws != NULL && ws->focused == c);
+            decorations_render(c, focused);
+            needs_redraw = true;
+        }
+    }
+
+    if (needs_redraw) {
+        panel_render_all();
+    }
+}

src/decorations.c

@@ -46,6 +46,8 @@ void decorations_render(Client *client, bool focused)
 
 void decorations_render_title_bar(Client *client, bool focused)
 {
+    (void)focused;
+
     if (client == NULL || client->frame == None) {
         return;
     }
@@ -59,8 +61,8 @@ void decorations_render_title_bar(Client *client, bool focused)
     int title_height = config_get_title_height();
     int border = client->border_width;
 
-    unsigned long bg_color = focused ? colors->title_focused_bg : colors->title_unfocused_bg;
-    unsigned long fg_color = focused ? colors->title_focused_fg : colors->title_unfocused_fg;
+    unsigned long bg_color = client_get_animated_title_color(client);
+    unsigned long fg_color = adjust_color_for_background(colors->title_focused_fg, bg_color);
 
     XSetForeground(dpy, dwn->gc, bg_color);
     XFillRectangle(dpy, client->frame, dwn->gc,
@@ -147,7 +149,7 @@ void decorations_render_buttons(Client *client, bool focused)
     }
 
     Display *dpy = dwn->display;
-    const ColorScheme *colors = config_get_colors();
+    (void)focused;
     int title_height = config_get_title_height();
     int border = client->border_width;
 
@@ -160,7 +162,7 @@ void decorations_render_buttons(Client *client, bool focused)
         return;
     }
 
-    unsigned long bg_color = focused ? colors->title_focused_bg : colors->title_unfocused_bg;
+    unsigned long bg_color = client_get_animated_title_color(client);
 
     XSetForeground(dpy, dwn->gc, bg_color);
     XFillRectangle(dpy, client->frame, dwn->gc, close_x, button_y, BUTTON_SIZE, BUTTON_SIZE);

src/main.c

@@ -773,6 +773,12 @@ int dwn_init(void)
         LOG_INFO("Loaded Xft font for UTF-8 support");
     }
 
+    dwn->xft_font_bold = XftFontOpenName(dwn->display, dwn->screen,
+                                          "monospace:size=10:bold:antialias=true");
+    if (dwn->xft_font_bold == NULL) {
+        dwn->xft_font_bold = dwn->xft_font;
+    }
+
     XGCValues gcv;
     gcv.foreground = dwn->config->colors.panel_fg;
     gcv.background = dwn->config->colors.panel_bg;
@@ -872,6 +878,9 @@ void dwn_cleanup(void)
     if (dwn->font != NULL) {
         XFreeFont(dwn->display, dwn->font);
     }
+    if (dwn->xft_font_bold != NULL && dwn->xft_font_bold != dwn->xft_font) {
+        XftFontClose(dwn->display, dwn->xft_font_bold);
+    }
     if (dwn->xft_font != NULL) {
         XftFontClose(dwn->display, dwn->xft_font);
     }
@@ -921,6 +930,8 @@ void dwn_run(void)
 
         demo_update();
 
+        client_update_animations();
+
         notifications_update();
 
         if (dwn->pending_focus_client != NULL) {

src/panel.c

@@ -68,12 +68,12 @@ static int panel_text_width(const char *text, int len)
     return 0;
 }
 
-static void panel_draw_text(Drawable d, int x, int y, const char *text,
-                            int len, unsigned long color)
+static void panel_draw_text_with_font(Drawable d, int x, int y, const char *text,
+                                       int len, unsigned long color, XftFont *font)
 {
     if (text == NULL || dwn == NULL || dwn->display == NULL) return;
 
-    if (dwn->xft_font != NULL) {
+    if (font != NULL) {
         XftDraw *xft_draw = XftDrawCreate(dwn->display, d,
                                           DefaultVisual(dwn->display, dwn->screen),
                                           dwn->colormap);
@@ -88,7 +88,7 @@ static void panel_draw_text(Drawable d, int x, int y, const char *text,
             XftColorAllocValue(dwn->display, DefaultVisual(dwn->display, dwn->screen),
                                dwn->colormap, &render_color, &xft_color);
 
-            XftDrawStringUtf8(xft_draw, &xft_color, dwn->xft_font,
+            XftDrawStringUtf8(xft_draw, &xft_color, font,
                               x, y, (const FcChar8 *)text, len);
 
             XftColorFree(dwn->display, DefaultVisual(dwn->display, dwn->screen),
@@ -102,6 +102,19 @@ static void panel_draw_text(Drawable d, int x, int y, const char *text,
     XDrawString(dwn->display, d, dwn->gc, x, y, text, len);
 }
 
+static void panel_draw_text(Drawable d, int x, int y, const char *text,
+                            int len, unsigned long color)
+{
+    panel_draw_text_with_font(d, x, y, text, len, color, dwn->xft_font);
+}
+
+static void panel_draw_text_bold(Drawable d, int x, int y, const char *text,
+                                  int len, unsigned long color)
+{
+    XftFont *font = dwn->xft_font_bold ? dwn->xft_font_bold : dwn->xft_font;
+    panel_draw_text_with_font(d, x, y, text, len, color, font);
+}
+
 static int panel_text_y(int panel_height)
 {
     if (dwn->xft_font != NULL) {
@@ -403,8 +416,6 @@ void panel_render_taskbar(Panel *panel, int x, int *width)
         unsigned long bg;
         if (minimized) {
             bg = colors->workspace_inactive;
-        } else if (focused) {
-            bg = colors->workspace_active;
         } else {
             bg = colors->panel_bg;
         }
@@ -444,12 +455,15 @@ void panel_render_taskbar(Panel *panel, int x, int *width)
         unsigned long fg;
         if (minimized) {
             fg = colors->panel_fg;
-        } else if (focused) {
-            fg = colors->panel_bg;
         } else {
-            fg = colors->panel_fg;
+            fg = c->taskbar_color;
+        }
+
+        if (focused && !minimized) {
+            panel_draw_text_bold(panel->buffer, current_x + 4, text_y, title, strlen(title), fg);
+        } else {
+            panel_draw_text(panel->buffer, current_x + 4, text_y, title, strlen(title), fg);
         }
-        panel_draw_text(panel->buffer, current_x + 4, text_y, title, strlen(title), fg);
 
         current_x += item_width;
     }

src/util.c

@@ -20,6 +20,7 @@
 #include <pthread.h>
 #include <stdatomic.h>
 #include <fcntl.h>
+#include <math.h>
 
 
 #define LOG_RING_SIZE 256
@@ -649,3 +650,148 @@ char *spawn_capture(const char *cmd)
 
     return output;
 }
+
+
+static void hsl_to_rgb(double h, double s, double l, int *r, int *g, int *b)
+{
+    double c = (1.0 - fabs(2.0 * l - 1.0)) * s;
+    double x = c * (1.0 - fabs(fmod(h / 60.0, 2.0) - 1.0));
+    double m = l - c / 2.0;
+
+    double rp = 0, gp = 0, bp = 0;
+
+    if (h < 60) {
+        rp = c; gp = x; bp = 0;
+    } else if (h < 120) {
+        rp = x; gp = c; bp = 0;
+    } else if (h < 180) {
+        rp = 0; gp = c; bp = x;
+    } else if (h < 240) {
+        rp = 0; gp = x; bp = c;
+    } else if (h < 300) {
+        rp = x; gp = 0; bp = c;
+    } else {
+        rp = c; gp = 0; bp = x;
+    }
+
+    *r = (int)((rp + m) * 255);
+    *g = (int)((gp + m) * 255);
+    *b = (int)((bp + m) * 255);
+}
+
+unsigned long rgb_to_pixel(int r, int g, int b)
+{
+    if (dwn == NULL || dwn->display == NULL) {
+        return 0;
+    }
+
+    XColor color;
+    color.red = (unsigned short)(r << 8);
+    color.green = (unsigned short)(g << 8);
+    color.blue = (unsigned short)(b << 8);
+    color.flags = DoRed | DoGreen | DoBlue;
+
+    if (XAllocColor(dwn->display, dwn->colormap, &color)) {
+        return color.pixel;
+    }
+
+    return (unsigned long)((r << 16) | (g << 8) | b);
+}
+
+unsigned long generate_unique_color(void)
+{
+    static unsigned int color_index = 0;
+    double golden_angle = 137.5;
+    double hue = fmod(color_index * golden_angle, 360.0);
+    color_index++;
+
+    double saturation = 0.75;
+    double lightness = 0.65;
+
+    int r, g, b;
+    hsl_to_rgb(hue, saturation, lightness, &r, &g, &b);
+
+    return rgb_to_pixel(r, g, b);
+}
+
+static double calculate_luminance(int r, int g, int b)
+{
+    double rs = r / 255.0;
+    double gs = g / 255.0;
+    double bs = b / 255.0;
+
+    rs = (rs <= 0.03928) ? rs / 12.92 : pow((rs + 0.055) / 1.055, 2.4);
+    gs = (gs <= 0.03928) ? gs / 12.92 : pow((gs + 0.055) / 1.055, 2.4);
+    bs = (bs <= 0.03928) ? bs / 12.92 : pow((bs + 0.055) / 1.055, 2.4);
+
+    return 0.2126 * rs + 0.7152 * gs + 0.0722 * bs;
+}
+
+unsigned long adjust_color_for_background(unsigned long color, unsigned long bg)
+{
+    int cr, cg, cb;
+    int br, bg_g, bb;
+
+    color_to_rgb(color, &cr, &cg, &cb);
+    color_to_rgb(bg, &br, &bg_g, &bb);
+
+    double color_lum = calculate_luminance(cr, cg, cb);
+    double bg_lum = calculate_luminance(br, bg_g, bb);
+
+    double lighter = (color_lum > bg_lum) ? color_lum : bg_lum;
+    double darker = (color_lum > bg_lum) ? bg_lum : color_lum;
+    double contrast = (lighter + 0.05) / (darker + 0.05);
+
+    if (contrast < 3.0) {
+        double factor = (bg_lum > 0.5) ? 0.3 : 1.8;
+        cr = (int)(cr * factor);
+        cg = (int)(cg * factor);
+        cb = (int)(cb * factor);
+
+        if (cr > 255) cr = 255;
+        if (cg > 255) cg = 255;
+        if (cb > 255) cb = 255;
+        if (cr < 0) cr = 0;
+        if (cg < 0) cg = 0;
+        if (cb < 0) cb = 0;
+    }
+
+    return rgb_to_pixel(cr, cg, cb);
+}
+
+unsigned long interpolate_color(unsigned long from, unsigned long to, float progress)
+{
+    if (progress <= 0.0f) return from;
+    if (progress >= 1.0f) return to;
+
+    int fr, fg_c, fb;
+    int tr, tg, tb;
+
+    color_to_rgb(from, &fr, &fg_c, &fb);
+    color_to_rgb(to, &tr, &tg, &tb);
+
+    int r = fr + (int)((tr - fr) * progress);
+    int g = fg_c + (int)((tg - fg_c) * progress);
+    int b = fb + (int)((tb - fb) * progress);
+
+    return rgb_to_pixel(r, g, b);
+}
+
+unsigned long dim_color(unsigned long color, float factor)
+{
+    int r, g, b;
+    color_to_rgb(color, &r, &g, &b);
+
+    r = (int)(r * factor);
+    g = (int)(g * factor);
+    b = (int)(b * factor);
+
+    if (r > 255) r = 255;
+    if (g > 255) g = 255;
+    if (b > 255) b = 255;
+    if (r < 0) r = 0;
+    if (g < 0) g = 0;
+    if (b < 0) b = 0;
+
+    return rgb_to_pixel(r, g, b);
+}