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Diffstat (limited to 'src/art_rgb_bitmap_affine.c')
| -rw-r--r-- | src/art_rgb_bitmap_affine.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/src/art_rgb_bitmap_affine.c b/src/art_rgb_bitmap_affine.c new file mode 100644 index 0000000..825f8b5 --- /dev/null +++ b/src/art_rgb_bitmap_affine.c @@ -0,0 +1,198 @@ +/* Libart_LGPL - library of basic graphic primitives + * Copyright (C) 1998 Raph Levien + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#include "config.h" +#include "art_rgb_bitmap_affine.h" + +#include <math.h> +#include "art_misc.h" +#include "art_point.h" +#include "art_affine.h" +#include "art_rgb_affine_private.h" + +/* This module handles compositing of affine-transformed bitmap images + over rgb pixel buffers. */ + +/* Composite the source image over the destination image, applying the + affine transform. Foreground color is given and assumed to be + opaque, background color is assumed to be fully transparent. */ + +static void +art_rgb_bitmap_affine_opaque (art_u8 *dst, + int x0, int y0, int x1, int y1, + int dst_rowstride, + const art_u8 *src, + int src_width, int src_height, int src_rowstride, + art_u32 rgb, + const double affine[6], + ArtFilterLevel level, + ArtAlphaGamma *alphagamma) +{ + /* Note: this is a slow implementation, and is missing all filter + levels other than NEAREST. It is here for clarity of presentation + and to establish the interface. */ + int x, y; + double inv[6]; + art_u8 *dst_p, *dst_linestart; + const art_u8 *src_p; + ArtPoint pt, src_pt; + int src_x, src_y; + art_u8 r, g, b; + int run_x0, run_x1; + + r = rgb >> 16; + g = (rgb >> 8) & 0xff; + b = rgb & 0xff; + dst_linestart = dst; + art_affine_invert (inv, affine); + for (y = y0; y < y1; y++) + { + pt.y = y + 0.5; + run_x0 = x0; + run_x1 = x1; + art_rgb_affine_run (&run_x0, &run_x1, y, src_width, src_height, + inv); + dst_p = dst_linestart + (run_x0 - x0) * 3; + for (x = run_x0; x < run_x1; x++) + { + pt.x = x + 0.5; + art_affine_point (&src_pt, &pt, inv); + src_x = floor (src_pt.x); + src_y = floor (src_pt.y); + src_p = src + (src_y * src_rowstride) + (src_x >> 3); + if (*src_p & (128 >> (src_x & 7))) + { + dst_p[0] = r; + dst_p[1] = g; + dst_p[2] = b; + } + dst_p += 3; + } + dst_linestart += dst_rowstride; + } +} +/* Composite the source image over the destination image, applying the + affine transform. Foreground color is given, background color is + assumed to be fully transparent. */ + +/** + * art_rgb_bitmap_affine: Affine transform source bitmap image and composite. + * @dst: Destination image RGB buffer. + * @x0: Left coordinate of destination rectangle. + * @y0: Top coordinate of destination rectangle. + * @x1: Right coordinate of destination rectangle. + * @y1: Bottom coordinate of destination rectangle. + * @dst_rowstride: Rowstride of @dst buffer. + * @src: Source image bitmap buffer. + * @src_width: Width of source image. + * @src_height: Height of source image. + * @src_rowstride: Rowstride of @src buffer. + * @rgba: RGBA foreground color, in 0xRRGGBBAA. + * @affine: Affine transform. + * @level: Filter level. + * @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing. + * + * Affine transform the source image stored in @src, compositing over + * the area of destination image @dst specified by the rectangle + * (@x0, @y0) - (@x1, @y1). + * + * The source bitmap stored with MSB as the leftmost pixel. Source 1 + * bits correspond to the semitransparent color @rgba, while source 0 + * bits are transparent. + * + * See art_rgb_affine() for a description of additional parameters. + **/ +void +art_rgb_bitmap_affine (art_u8 *dst, + int x0, int y0, int x1, int y1, int dst_rowstride, + const art_u8 *src, + int src_width, int src_height, int src_rowstride, + art_u32 rgba, + const double affine[6], + ArtFilterLevel level, + ArtAlphaGamma *alphagamma) +{ + /* Note: this is a slow implementation, and is missing all filter + levels other than NEAREST. It is here for clarity of presentation + and to establish the interface. */ + int x, y; + double inv[6]; + art_u8 *dst_p, *dst_linestart; + const art_u8 *src_p; + ArtPoint pt, src_pt; + int src_x, src_y; + int alpha; + art_u8 bg_r, bg_g, bg_b; + art_u8 fg_r, fg_g, fg_b; + art_u8 r, g, b; + int run_x0, run_x1; + + alpha = rgba & 0xff; + if (alpha == 0xff) + { + art_rgb_bitmap_affine_opaque (dst, x0, y0, x1, y1, dst_rowstride, + src, + src_width, src_height, src_rowstride, + rgba >> 8, + affine, + level, + alphagamma); + return; + } + /* alpha = (65536 * alpha) / 255; */ + alpha = (alpha << 8) + alpha + (alpha >> 7); + r = rgba >> 24; + g = (rgba >> 16) & 0xff; + b = (rgba >> 8) & 0xff; + dst_linestart = dst; + art_affine_invert (inv, affine); + for (y = y0; y < y1; y++) + { + pt.y = y + 0.5; + run_x0 = x0; + run_x1 = x1; + art_rgb_affine_run (&run_x0, &run_x1, y, src_width, src_height, + inv); + dst_p = dst_linestart + (run_x0 - x0) * 3; + for (x = run_x0; x < run_x1; x++) + { + pt.x = x + 0.5; + art_affine_point (&src_pt, &pt, inv); + src_x = floor (src_pt.x); + src_y = floor (src_pt.y); + src_p = src + (src_y * src_rowstride) + (src_x >> 3); + if (*src_p & (128 >> (src_x & 7))) + { + bg_r = dst_p[0]; + bg_g = dst_p[1]; + bg_b = dst_p[2]; + + fg_r = bg_r + (((r - bg_r) * alpha + 0x8000) >> 16); + fg_g = bg_g + (((g - bg_g) * alpha + 0x8000) >> 16); + fg_b = bg_b + (((b - bg_b) * alpha + 0x8000) >> 16); + + dst_p[0] = fg_r; + dst_p[1] = fg_g; + dst_p[2] = fg_b; + } + dst_p += 3; + } + dst_linestart += dst_rowstride; + } +} |