Merge pull request #58 from weihsinyeh/drop_shadow

Render drop shadow for active window

Author: jserv

apps/multi.c

@@ -4,9 +4,11 @@
  * All rights reserved.
  */
 
+#include <stddef.h>
 #include "apps_multi.h"
 
 #define D(x) twin_double_to_fixed(x)
+#define ASSET_PATH "assets/"
 
 static void apps_line_start(twin_screen_t *screen, int x, int y, int w, int h)
 {
@@ -272,6 +274,55 @@ static void apps_flower_start(twin_screen_t *screen, int x, int y, int w, int h)
     twin_window_show(window);
 }
 
+static void apps_blur(twin_screen_t *screen, int x, int y, int w, int h)
+{
+    twin_pixmap_t *raw_background = NULL;
+#if defined(CONFIG_LOADER_PNG)
+    raw_background = twin_pixmap_from_file(ASSET_PATH "tux.png", TWIN_ARGB32);
+#endif
+    if (!raw_background)
+        return;
+    twin_window_t *window = twin_window_create(
+        screen, TWIN_ARGB32, TwinWindowApplication, x, y, w, h);
+    twin_window_set_name(window, "Blur");
+    twin_pixmap_t *scaled_background = twin_pixmap_create(
+        TWIN_ARGB32, window->pixmap->width, window->pixmap->height);
+    twin_fixed_t sx, sy;
+    sx = twin_fixed_div(
+        twin_int_to_fixed(raw_background->width),
+        twin_int_to_fixed(window->client.right - window->client.left));
+    sy = twin_fixed_div(
+        twin_int_to_fixed(raw_background->height),
+        twin_int_to_fixed(window->client.bottom - window->client.top));
+
+    twin_matrix_scale(&raw_background->transform, sx, sy);
+    twin_operand_t srcop = {
+        .source_kind = TWIN_PIXMAP,
+        .u.pixmap = raw_background,
+    };
+
+    twin_composite(scaled_background, 0, 0, &srcop, 0, 0, 0, 0, 0, TWIN_SOURCE,
+                   scaled_background->width, scaled_background->height);
+
+    twin_pointer_t src, dst;
+    for (int y = window->client.top; y < window->client.bottom; y++)
+        for (int x = window->client.left; x < window->client.right; x++) {
+            src =
+                twin_pixmap_pointer(scaled_background, x - window->client.left,
+                                    y - window->client.top);
+            dst = twin_pixmap_pointer(window->pixmap, x, y);
+            *dst.argb32 = *src.argb32 | 0xff000000;
+        }
+    twin_stack_blur(window->pixmap, 5, window->client.left,
+                    window->client.right, window->client.top,
+                    window->client.bottom);
+
+    twin_pixmap_destroy(scaled_background);
+    twin_pixmap_destroy(raw_background);
+    twin_window_show(window);
+    return;
+}
+
 void apps_multi_start(twin_screen_t *screen,
                       const char *name,
                       int x,
@@ -286,4 +337,5 @@ void apps_multi_start(twin_screen_t *screen,
     apps_ascii_start(screen, x += 20, y += 20, w, h);
     apps_jelly_start(screen, x += 20, y += 20, w / 2, h);
     apps_flower_start(screen, x += 20, y += 20, w, h);
+    apps_blur(screen, x += 20, y += 20, w / 2, h / 2);
 }

configs/Kconfig

@@ -55,6 +55,28 @@ config CURSOR
     default n
     depends on !BACKEND_VNC
 
+config DROP_SHADOW
+    bool "Render drop shadow for active window"
+    default y
+
+config HORIZONTAL_OFFSET
+    int "Horizontal offset"
+    default 1
+    range 1 10
+    depends on DROP_SHADOW
+
+config VERTICAL_OFFSET
+    int "Vertical offset"
+    default 1
+    range 1 10
+    depends on DROP_SHADOW
+
+config SHADOW_BLUR
+    int "Shadow blur radius"
+    default 10
+    range 1 10
+    depends on DROP_SHADOW
+
 endmenu
 
 menu "Image Loaders"

include/twin.h

@@ -195,6 +195,15 @@ typedef struct _twin_pixmap {
      * Pixels
      */
     twin_animation_t *animation;
+
+#if defined(CONFIG_DROP_SHADOW)
+    /*
+     * When the pixel map is within the active window, it will have a drop
+     * shadow to enhance its visual distinction.
+     */
+    bool shadow;
+#endif
+
     twin_pointer_t p;
     /*
      * When representing a window, this point
@@ -423,6 +432,13 @@ typedef void (*twin_destroy_func_t)(twin_window_t *window);
 struct _twin_window {
     twin_screen_t *screen;
     twin_pixmap_t *pixmap;
+
+#if defined(CONFIG_DROP_SHADOW)
+    /* Set the shadow range for horizontal and vertical directions. */
+    twin_coord_t shadow_x;
+    twin_coord_t shadow_y;
+#endif
+
     twin_window_style_t style;
     twin_rect_t client;
     twin_rect_t damage;
@@ -652,8 +668,26 @@ void twin_fill(twin_pixmap_t *dst,
  * draw-common.c
  */
 
+/* Blur the specified area in the pixel map. */
+void twin_stack_blur(twin_pixmap_t *px,
+                     int radius,
+                     twin_coord_t left,
+                     twin_coord_t right,
+                     twin_coord_t top,
+                     twin_coord_t bottom);
+
 void twin_premultiply_alpha(twin_pixmap_t *px);
 
+/*
+ * Overwrite the original pixel values for a specified number of pixels in
+ * width.
+ */
+void twin_cover(twin_pixmap_t *dst,
+                twin_argb32_t color,
+                twin_coord_t x,
+                twin_coord_t y,
+                twin_coord_t width);
+
 /*
  * event.c
  */

include/twin_private.h

@@ -181,13 +181,51 @@ typedef int64_t twin_xfixed_t;
     (((t) = twin_get_8(d, i) + twin_get_8(s, i)), (twin_argb32_t) twin_sat(t) \
                                                       << (i))
 
+#define _twin_add_ARGB(s, d, i, t) (((t) = (s) + twin_get_8(d, i)))
+#define _twin_add(s, d, t) (((t) = (s) + (d)))
+#define _twin_div(d, den, i, t)                     \
+    (((t) = (d) / (den)), (t) = twin_get_8((t), 0), \
+     (twin_argb32_t) twin_sat(t) << (i))
+#define _twin_sub_ARGB(s, d, i, t) (((t) = (s) - twin_get_8(d, i)))
+#define _twin_sub(s, d, t) (((t) = (s) - (d)))
+#define twin_put_8(d, i, t) (((t) = (d) << (i)))
+
 #define twin_argb32_to_rgb16(s) \
     ((((s) >> 3) & 0x001f) | (((s) >> 5) & 0x07e0) | (((s) >> 8) & 0xf800))
 #define twin_rgb16_to_argb32(s)                       \
     (((((s) << 3) & 0xf8) | (((s) >> 2) & 0x7)) |     \
      ((((s) << 5) & 0xfc00) | (((s) >> 1) & 0x300)) | \
      ((((s) << 8) & 0xf80000) | (((s) << 3) & 0x70000)) | 0xff000000)
 
+#ifndef min
+#if defined(__GNUC__) || defined(__clang__)
+#define min(x, y)            \
+    ({                       \
+        typeof(x) _x = (x);  \
+        typeof(y) _y = (y);  \
+        (void) (&_x == &_y); \
+        _x < _y ? _x : _y;   \
+    })
+#else
+/* Generic implementation: potential side effects */
+#define min(x, y) ((x) < (y) ? (x) : (y))
+#endif
+#endif
+#ifndef max
+#if defined(__GNUC__) || defined(__clang__)
+#define max(x, y)            \
+    ({                       \
+        typeof(x) _x = (x);  \
+        typeof(y) _y = (y);  \
+        (void) (&_x == &_y); \
+        _x > _y ? _x : _y;   \
+    })
+#else
+/* Generic implementation: potential side effects */
+#define max(x, y) ((x) > (y) ? (x) : (y))
+#endif
+#endif
+
 typedef union {
     twin_pointer_t p;
     twin_argb32_t c;
@@ -468,7 +506,7 @@ void _twin_path_sfinish(twin_path_t *path);
 #define twin_glyph_snap_y(g) (twin_glyph_snap_x(g) + twin_glyph_n_snap_x(g))
 
 /*
- * dispatch stuff
+ * Dispatch stuff
  */
 typedef struct _twin_queue {
     struct _twin_queue *next;
@@ -593,6 +631,21 @@ void _twin_button_init(twin_button_t *button,
                        twin_style_t font_style,
                        twin_dispatch_proc_t dispatch);
 
+/*
+ * Visual effect stuff
+ */
+
+#if defined(CONFIG_DROP_SHADOW)
+/*
+ * Add a shadow with the specified color, horizontal offset, and vertical
+ * offset.
+ */
+void twin_shadow_border(twin_pixmap_t *shadow,
+                        twin_argb32_t color,
+                        twin_coord_t shift_x,
+                        twin_coord_t shift_y);
+#endif
+
 /* utility */
 
 #ifdef _MSC_VER