/* 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_affine.h" #include #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 rgb images over rgb pixel buffers. */ /** * art_rgb_affine: Affine transform source RGB 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 RGB buffer. * @src_width: Width of source image. * @src_height: Height of source image. * @src_rowstride: Rowstride of @src buffer. * @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). As usual in libart, the left and top edges * of this rectangle are included, and the right and bottom edges are * excluded. * * The @alphagamma parameter specifies that the alpha compositing be done * in a gamma-corrected color space. Since the source image is opaque RGB, * this argument only affects the edges. In the current implementation, * it is ignored. * * The @level parameter specifies the speed/quality tradeoff of the * image interpolation. Currently, only ART_FILTER_NEAREST is * implemented. **/ void art_rgb_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, 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 run_x0, run_x1; 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; dst_p[0] = src_p[0]; dst_p[1] = src_p[1]; dst_p[2] = src_p[2]; dst_p += 3; } dst_linestart += dst_rowstride; } }