1 | /* Libart_LGPL - library of basic graphic primitives |
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2 | * Copyright (C) 1998 Raph Levien |
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3 | * |
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4 | * This library is free software; you can redistribute it and/or |
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5 | * modify it under the terms of the GNU Library General Public |
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6 | * License as published by the Free Software Foundation; either |
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7 | * version 2 of the License, or (at your option) any later version. |
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8 | * |
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9 | * This library is distributed in the hope that it will be useful, |
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10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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12 | * Library General Public License for more details. |
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13 | * |
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14 | * You should have received a copy of the GNU Library General Public |
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15 | * License along with this library; if not, write to the |
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16 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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17 | * Boston, MA 02111-1307, USA. |
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18 | */ |
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19 | |
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20 | #include "config.h" |
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21 | #include "art_rgb_affine.h" |
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22 | |
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23 | #include <math.h> |
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24 | #include "art_misc.h" |
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25 | #include "art_point.h" |
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26 | #include "art_affine.h" |
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27 | #include "art_rgb_affine_private.h" |
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28 | |
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29 | /* This module handles compositing of affine-transformed rgb images |
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30 | over rgb pixel buffers. */ |
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31 | |
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32 | /** |
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33 | * art_rgb_affine: Affine transform source RGB image and composite. |
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34 | * @dst: Destination image RGB buffer. |
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35 | * @x0: Left coordinate of destination rectangle. |
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36 | * @y0: Top coordinate of destination rectangle. |
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37 | * @x1: Right coordinate of destination rectangle. |
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38 | * @y1: Bottom coordinate of destination rectangle. |
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39 | * @dst_rowstride: Rowstride of @dst buffer. |
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40 | * @src: Source image RGB buffer. |
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41 | * @src_width: Width of source image. |
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42 | * @src_height: Height of source image. |
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43 | * @src_rowstride: Rowstride of @src buffer. |
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44 | * @affine: Affine transform. |
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45 | * @level: Filter level. |
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46 | * @alphagamma: #ArtAlphaGamma for gamma-correcting the compositing. |
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47 | * |
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48 | * Affine transform the source image stored in @src, compositing over |
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49 | * the area of destination image @dst specified by the rectangle |
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50 | * (@x0, @y0) - (@x1, @y1). As usual in libart, the left and top edges |
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51 | * of this rectangle are included, and the right and bottom edges are |
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52 | * excluded. |
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53 | * |
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54 | * The @alphagamma parameter specifies that the alpha compositing be done |
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55 | * in a gamma-corrected color space. Since the source image is opaque RGB, |
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56 | * this argument only affects the edges. In the current implementation, |
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57 | * it is ignored. |
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58 | * |
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59 | * The @level parameter specifies the speed/quality tradeoff of the |
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60 | * image interpolation. Currently, only ART_FILTER_NEAREST is |
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61 | * implemented. |
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62 | **/ |
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63 | void |
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64 | art_rgb_affine (art_u8 *dst, int x0, int y0, int x1, int y1, int dst_rowstride, |
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65 | const art_u8 *src, |
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66 | int src_width, int src_height, int src_rowstride, |
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67 | const double affine[6], |
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68 | ArtFilterLevel level, |
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69 | ArtAlphaGamma *alphagamma) |
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70 | { |
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71 | /* Note: this is a slow implementation, and is missing all filter |
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72 | levels other than NEAREST. It is here for clarity of presentation |
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73 | and to establish the interface. */ |
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74 | int x, y; |
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75 | double inv[6]; |
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76 | art_u8 *dst_p, *dst_linestart; |
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77 | const art_u8 *src_p; |
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78 | ArtPoint pt, src_pt; |
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79 | int src_x, src_y; |
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80 | int run_x0, run_x1; |
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81 | |
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82 | dst_linestart = dst; |
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83 | art_affine_invert (inv, affine); |
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84 | for (y = y0; y < y1; y++) |
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85 | { |
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86 | pt.y = y + 0.5; |
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87 | run_x0 = x0; |
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88 | run_x1 = x1; |
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89 | art_rgb_affine_run (&run_x0, &run_x1, y, src_width, src_height, |
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90 | inv); |
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91 | dst_p = dst_linestart + (run_x0 - x0) * 3; |
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92 | for (x = run_x0; x < run_x1; x++) |
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93 | { |
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94 | pt.x = x + 0.5; |
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95 | art_affine_point (&src_pt, &pt, inv); |
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96 | src_x = floor (src_pt.x); |
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97 | src_y = floor (src_pt.y); |
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98 | src_p = src + (src_y * src_rowstride) + src_x * 3; |
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99 | dst_p[0] = src_p[0]; |
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100 | dst_p[1] = src_p[1]; |
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101 | dst_p[2] = src_p[2]; |
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102 | dst_p += 3; |
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103 | } |
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104 | dst_linestart += dst_rowstride; |
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105 | } |
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106 | } |
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