static void premultiply_data(png_structp png, png_row_infop row_info, png_bytep data) { unsigned int i; png_bytep p; for (i = 0, p = data; i < row_info->rowbytes; i += 4, p += 4) { png_byte alpha = p[3]; uint32_t w; if (alpha == 0) { w = 0; } else { png_byte red = p[0]; png_byte green = p[1]; png_byte blue = p[2]; if (alpha != 0xff) { red = multiply_alpha(alpha, red); green = multiply_alpha(alpha, green); blue = multiply_alpha(alpha, blue); } w = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0); } * (uint32_t *) p = w; } }
/* Premultiplies data and converts RGBA bytes => native endian. */ static void premultiply_data( png_structp png, png_row_infop row_info, png_bytep data ) { unsigned int i; FT_UNUSED( png ); for ( i = 0; i < row_info->rowbytes; i += 4 ) { unsigned char* base = &data[i]; unsigned int alpha = base[3]; if ( alpha == 0 ) base[0] = base[1] = base[2] = base[3] = 0; else { unsigned int red = base[0]; unsigned int green = base[1]; unsigned int blue = base[2]; if ( alpha != 0xFF ) { red = multiply_alpha( alpha, red ); green = multiply_alpha( alpha, green ); blue = multiply_alpha( alpha, blue ); } base[0] = blue; base[1] = green; base[2] = red; base[3] = alpha; } } }
static void gauss_rle (GimpDrawable *drawable, gdouble radius, gint pass, gboolean show_progress) { GimpPixelRgn src_rgn, dest_rgn; gint width, height; gint bytes; gint has_alpha; guchar *dest, *dp; guchar *src, *sp; gint *buf, *bb; gint pixels; gint total = 1; gint x1, y1, x2, y2; gint i, row, col, b; gint start, end; gdouble progress, max_progress; gint *curve; gint *sum = NULL; gint val; gint length; gint initial_p, initial_m; gdouble std_dev; if (radius <= 0.0) return; gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2); width = (x2 - x1); height = (y2 - y1); if (width < 1 || height < 1) return; bytes = drawable->bpp; has_alpha = gimp_drawable_has_alpha(drawable->drawable_id); buf = g_new (gint, MAX (width, height) * 2); /* allocate buffers for source and destination pixels */ src = g_new (guchar, MAX (width, height) * bytes); dest = g_new (guchar, MAX (width, height) * bytes); gimp_pixel_rgn_init (&src_rgn, drawable, 0, 0, drawable->width, drawable->height, FALSE, FALSE); gimp_pixel_rgn_init (&dest_rgn, drawable, 0, 0, drawable->width, drawable->height, TRUE, TRUE); progress = 0.0; max_progress = 2 * width * height; /* First the vertical pass */ radius = fabs (radius) + 1.0; std_dev = sqrt (-(radius * radius) / (2 * log (1.0 / 255.0))); curve = make_curve (std_dev, &length); sum = g_new (gint, 2 * length + 1); sum[0] = 0; for (i = 1; i <= length*2; i++) sum[i] = curve[i-length-1] + sum[i-1]; sum += length; total = sum[length] - sum[-length]; for (col = 0; col < width; col++) { gimp_pixel_rgn_get_col (&src_rgn, src, col + x1, y1, (y2 - y1)); if (has_alpha) multiply_alpha (src, height, bytes); sp = src; dp = dest; for (b = 0; b < bytes; b++) { initial_p = sp[b]; initial_m = sp[(height-1) * bytes + b]; /* Determine a run-length encoded version of the row */ run_length_encode (sp + b, buf, bytes, height); for (row = 0; row < height; row++) { start = (row < length) ? -row : -length; end = (height <= (row + length) ? (height - row - 1) : length); val = 0; i = start; bb = buf + (row + i) * 2; if (start != -length) val += initial_p * (sum[start] - sum[-length]); while (i < end) { pixels = bb[0]; i += pixels; if (i > end) i = end; val += bb[1] * (sum[i] - sum[start]); bb += (pixels * 2); start = i; } if (end != length) val += initial_m * (sum[length] - sum[end]); dp[row * bytes + b] = val / total; } } if (has_alpha) separate_alpha (dest, height, bytes); gimp_pixel_rgn_set_col (&dest_rgn, dest, col + x1, y1, (y2 - y1)); if (show_progress) { progress += height; if ((col % 32) == 0) gimp_progress_update (0.5 * (pass + (progress / max_progress))); } } /* prepare for the horizontal pass */ gimp_pixel_rgn_init (&src_rgn, drawable, 0, 0, drawable->width, drawable->height, FALSE, TRUE); /* Now the horizontal pass */ for (row = 0; row < height; row++) { gimp_pixel_rgn_get_row (&src_rgn, src, x1, row + y1, (x2 - x1)); if (has_alpha) multiply_alpha (src, width, bytes); sp = src; dp = dest; for (b = 0; b < bytes; b++) { initial_p = sp[b]; initial_m = sp[(width-1) * bytes + b]; /* Determine a run-length encoded version of the row */ run_length_encode (sp + b, buf, bytes, width); for (col = 0; col < width; col++) { start = (col < length) ? -col : -length; end = (width <= (col + length)) ? (width - col - 1) : length; val = 0; i = start; bb = buf + (col + i) * 2; if (start != -length) val += initial_p * (sum[start] - sum[-length]); while (i < end) { pixels = bb[0]; i += pixels; if (i > end) i = end; val += bb[1] * (sum[i] - sum[start]); bb += (pixels * 2); start = i; } if (end != length) val += initial_m * (sum[length] - sum[end]); dp[col * bytes + b] = val / total; } } if (has_alpha) separate_alpha (dest, width, bytes); gimp_pixel_rgn_set_row (&dest_rgn, dest, x1, row + y1, (x2 - x1)); if (show_progress) { progress += width; if ((row % 32) == 0) gimp_progress_update (0.5 * (pass + (progress / max_progress))); } } /* merge the shadow, update the drawable */ gimp_drawable_flush (drawable); gimp_drawable_merge_shadow (drawable->drawable_id, TRUE); gimp_drawable_update (drawable->drawable_id, x1, y1, (x2 - x1), (y2 - y1)); /* free buffers */ g_free (buf); g_free (src); g_free (dest); }