| Re: [AD] translucent fonts |
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On Thu, 2006-01-05 at 13:52 +0100, Elias Pschernig wrote:
> One way around that would be to only use the top-left corner pixel as
> background color for 32-bit alpha fonts, and keep 0 for 8-bit and yellow
> for 15/16/24-bit and opaque 32-bit ones.
>
Attached is a patch which does that. Since it was the 3rd location to
define a bitmap_has_alpha(), the patch makes it an API function. And the
API toget alpha font drawing is now to use make_trans_font() on a font
to switch its vtable, and no more state.
--
Elias Pschernig
Index: include/allegro/font.h
===================================================================
--- include/allegro/font.h (revision 5626)
+++ include/allegro/font.h (working copy)
@@ -41,6 +41,8 @@
struct FONT_VTABLE *vtable;
} FONT;
+AL_FUNC(void, make_trans_font, (FONT *f));
+
AL_FUNC(int, is_color_font, (FONT *f));
AL_FUNC(int, is_mono_font, (FONT *f));
AL_FUNC(int, is_compatible_font, (FONT *f1, FONT *f2));
Index: include/allegro/internal/aintern.h
===================================================================
--- include/allegro/internal/aintern.h (revision 5626)
+++ include/allegro/internal/aintern.h (working copy)
@@ -262,6 +262,8 @@
AL_VAR(FONT_VTABLE *, font_vtable_mono);
AL_VAR(FONT_VTABLE, _font_vtable_color);
AL_VAR(FONT_VTABLE *, font_vtable_color);
+AL_VAR(FONT_VTABLE, _font_vtable_trans);
+AL_VAR(FONT_VTABLE *, font_vtable_trans);
AL_FUNC(FONT_GLYPH *, _mono_find_glyph, (AL_CONST FONT *f, int ch));
AL_FUNC(BITMAP *, _color_find_glyph, (AL_CONST FONT *f, int ch));
Index: src/font.c
===================================================================
--- src/font.c (revision 5626)
+++ src/font.c (working copy)
@@ -921,7 +921,7 @@
}
else {
if (bitmap_color_depth(g) == bitmap_color_depth(bmp)) {
- masked_blit(g, bmp, 0, 0, x, y + (h-g->h)/2, g->w, g->h);
+ masked_blit(g, bmp, 0, 0, x, y + (h-g->h)/2, g->w, g->h);
}
else {
int color_conv_mode;
@@ -952,6 +952,38 @@
+/* trans_render_char:
+ * (trans vtable entry)
+ *
+ * Renders a transparent character onto a bitmap, at the specified location,
+ * using the specified colors. fg is ignored. if bg == -1, render as
+ * transparent, else render as opaque. Returns the character width, in pixels.
+ */
+static int trans_render_char(AL_CONST FONT* f, int ch, int fg, int bg, BITMAP* bmp, int x, int y)
+{
+ int w = 0;
+ int h = f->vtable->font_height(f);
+ BITMAP *g = 0;
+
+ acquire_bitmap(bmp);
+
+ if(bg >= 0) {
+ rectfill(bmp, x, y, x + f->vtable->char_length(f, ch) - 1, y + h - 1, bg);
+ }
+
+ g = _color_find_glyph(f, ch);
+ if(g) {
+ draw_trans_sprite(bmp, g, x, y + (h-g->h)/2);
+ w = g->w;
+ }
+
+ release_bitmap(bmp);
+
+ return w;
+}
+
+
+
/* color_render:
* (color vtable entry)
* Renders a color font onto a bitmap, at the specified location, using
@@ -1393,8 +1425,39 @@
FONT_VTABLE* font_vtable_color = &_font_vtable_color;
+FONT_VTABLE _font_vtable_trans = {
+ font_height,
+ color_char_length,
+ length,
+ trans_render_char,
+ color_render,
+ color_destroy,
+ color_get_font_ranges,
+ color_get_font_range_begin,
+ color_get_font_range_end,
+ color_extract_font_range,
+ color_merge_fonts,
+ color_transpose_font
+};
+FONT_VTABLE* font_vtable_trans = &_font_vtable_trans;
+
+
+
+/* make_trans_font:
+ * Modifes a font so glyphs are drawn with draw_trans_sprite.
+ */
+void make_trans_font(FONT *f)
+{
+ ASSERT(f);
+ ASSERT(f->vtable == font_vtable_color);
+
+ f->vtable = font_vtable_trans;
+}
+
+
+
/* is_color_font:
* returns non-zero if the font passed is a bitmapped colour font
*/
Index: src/fontbmp.c
===================================================================
--- src/fontbmp.c (revision 5626)
+++ src/fontbmp.c (working copy)
@@ -32,7 +32,10 @@
{
int c;
- if (bitmap_color_depth(bmp) == 8) {
+ if (bitmap_has_alpha(bmp)) {
+ c = getpixel(bmp, 0, 0);
+ }
+ else if (bitmap_color_depth(bmp) == 8) {
c = 255;
}
else {
Index: src/gfx.c
===================================================================
--- src/gfx.c (revision 5626)
+++ src/gfx.c (working copy)
@@ -163,6 +163,29 @@
+/* bitmap_has_alpha:
+ * Checks whether this bitmap has an alpha channel.
+ */
+int bitmap_has_alpha(BITMAP *bmp)
+{
+ int x, y, c;
+
+ if (bitmap_color_depth(bmp) != 32)
+ return FALSE;
+
+ for (y = 0; y < bmp->h; y++) {
+ for (x = 0; x < bmp->w; x++) {
+ c = getpixel(bmp, x, y);
+ if (geta32(c))
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+
+
/* vsync:
* Waits for a retrace.
*/
Index: src/tga.c
===================================================================
--- src/tga.c (revision 5626)
+++ src/tga.c (working copy)
@@ -470,29 +470,6 @@
-/* bitmap_has_alpha:
- * Checks whether this bitmap has an alpha channel.
- */
-static int bitmap_has_alpha(BITMAP *bmp)
-{
- int x, y, c;
-
- if (bitmap_color_depth(bmp) != 32)
- return FALSE;
-
- for (y = 0; y < bmp->h; y++) {
- for (x = 0; x < bmp->w; x++) {
- c = getpixel(bmp, x, y);
- if (geta32(c))
- return TRUE;
- }
- }
-
- return FALSE;
-}
-
-
-
/* save_tga:
* Writes a bitmap into a TGA file, using the specified palette (this
* should be an array of at least 256 RGB structures).
Index: tools/plugins/datimage.c
===================================================================
--- tools/plugins/datimage.c (revision 5626)
+++ tools/plugins/datimage.c (working copy)
@@ -27,27 +27,6 @@
-/* checks whether this bitmap has an alpha channel */
-static int bitmap_has_alpha(BITMAP *bmp)
-{
- int x, y, c;
-
- if (bitmap_color_depth(bmp) != 32)
- return FALSE;
-
- for (y=0; y<bmp->h; y++) {
- for (x=0; x<bmp->w; x++) {
- c = getpixel(bmp, x, y);
- if (geta32(c))
- return TRUE;
- }
- }
-
- return FALSE;
-}
-
-
-
/* checks whether this RLE sprite has an alpha channel */
static int rle_has_alpha(AL_CONST RLE_SPRITE *spr)
{