[22324] | 1 | /* |
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| 2 | * art_render_mask.c: Alpha mask source for modular rendering. |
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| 3 | * |
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| 4 | * Libart_LGPL - library of basic graphic primitives |
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| 5 | * Copyright (C) 2000 Raph Levien |
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| 6 | * |
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| 7 | * This library is free software; you can redistribute it and/or |
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| 8 | * modify it under the terms of the GNU Library General Public |
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| 9 | * License as published by the Free Software Foundation; either |
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| 10 | * version 2 of the License, or (at your option) any later version. |
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| 11 | * |
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| 12 | * This library is distributed in the hope that it will be useful, |
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 15 | * Library General Public License for more details. |
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| 16 | * |
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| 17 | * You should have received a copy of the GNU Library General Public |
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| 18 | * License along with this library; if not, write to the |
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| 19 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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| 20 | * Boston, MA 02111-1307, USA. |
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| 21 | * |
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| 22 | * Authors: Raph Levien <raph@acm.org> |
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| 23 | */ |
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| 24 | |
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| 25 | #include "config.h" |
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| 26 | #include "art_render_mask.h" |
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| 27 | |
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| 28 | #include <string.h> |
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| 29 | |
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| 30 | |
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| 31 | typedef struct _ArtMaskSourceMask ArtMaskSourceMask; |
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| 32 | |
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| 33 | struct _ArtMaskSourceMask { |
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| 34 | ArtMaskSource super; |
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| 35 | ArtRender *render; |
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| 36 | art_boolean first; |
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| 37 | int x0; |
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| 38 | int y0; |
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| 39 | int x1; |
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| 40 | int y1; |
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| 41 | const art_u8 *mask_buf; |
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| 42 | int rowstride; |
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| 43 | }; |
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| 44 | |
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| 45 | static void |
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| 46 | art_render_mask_done (ArtRenderCallback *self, ArtRender *render) |
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| 47 | { |
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| 48 | art_free (self); |
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| 49 | } |
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| 50 | |
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| 51 | static int |
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| 52 | art_render_mask_can_drive (ArtMaskSource *self, ArtRender *render) |
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| 53 | { |
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| 54 | return 0; |
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| 55 | } |
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| 56 | |
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| 57 | static void |
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| 58 | art_render_mask_render (ArtRenderCallback *self, ArtRender *render, |
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| 59 | art_u8 *dest, int y) |
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| 60 | { |
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| 61 | ArtMaskSourceMask *z = (ArtMaskSourceMask *)self; |
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| 62 | int x0 = render->x0, x1 = render->x1; |
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| 63 | int z_x0 = z->x0, z_x1 = z->x1; |
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| 64 | int width = x1 - x0; |
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| 65 | int z_width = z_x1 - z_x0; |
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| 66 | art_u8 *alpha_buf = render->alpha_buf; |
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| 67 | |
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| 68 | if (y < z->y0 || y >= z->y1 || z_width <= 0) |
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| 69 | memset (alpha_buf, 0, width); |
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| 70 | else |
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| 71 | { |
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| 72 | const art_u8 *src_line = z->mask_buf + (y - z->y0) * z->rowstride; |
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| 73 | art_u8 *dst_line = alpha_buf + z_x0 - x0; |
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| 74 | |
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| 75 | if (z_x0 > x0) |
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| 76 | memset (alpha_buf, 0, z_x0 - x0); |
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| 77 | |
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| 78 | if (z->first) |
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| 79 | memcpy (dst_line, src_line, z_width); |
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| 80 | else |
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| 81 | { |
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| 82 | int x; |
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| 83 | |
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| 84 | for (x = 0; x < z_width; x++) |
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| 85 | { |
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| 86 | int v; |
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| 87 | v = src_line[x]; |
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| 88 | if (v) |
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| 89 | { |
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| 90 | v = v * dst_line[x] + 0x80; |
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| 91 | v = (v + (v >> 8)) >> 8; |
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| 92 | dst_line[x] = v; |
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| 93 | } |
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| 94 | else |
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| 95 | { |
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| 96 | dst_line[x] = 0; |
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| 97 | } |
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| 98 | } |
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| 99 | } |
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| 100 | |
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| 101 | if (z_x1 < x1) |
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| 102 | memset (alpha_buf + z_x1 - x0, 0, x1 - z_x1); |
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| 103 | } |
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| 104 | } |
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| 105 | |
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| 106 | static void |
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| 107 | art_render_mask_prepare (ArtMaskSource *self, ArtRender *render, |
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| 108 | art_boolean first) |
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| 109 | { |
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| 110 | ArtMaskSourceMask *z = (ArtMaskSourceMask *)self; |
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| 111 | self->super.render = art_render_mask_render; |
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| 112 | z->first = first; |
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| 113 | } |
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| 114 | |
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| 115 | /** |
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| 116 | * art_render_mask: Use an alpha buffer as a render mask source. |
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| 117 | * @render: Render object. |
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| 118 | * @x0: Left coordinate of mask rect. |
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| 119 | * @y0: Top coordinate of mask rect. |
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| 120 | * @x1: Right coordinate of mask rect. |
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| 121 | * @y1: Bottom coordinate of mask rect. |
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| 122 | * @mask_buf: Buffer containing 8bpp alpha mask data. |
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| 123 | * @rowstride: Rowstride of @mask_buf. |
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| 124 | * |
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| 125 | * Adds @mask_buf to the render object as a mask. Note: @mask_buf must |
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| 126 | * remain allocated until art_render_invoke() is called on @render. |
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| 127 | **/ |
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| 128 | void |
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| 129 | art_render_mask (ArtRender *render, |
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| 130 | int x0, int y0, int x1, int y1, |
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| 131 | const art_u8 *mask_buf, int rowstride) |
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| 132 | { |
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| 133 | ArtMaskSourceMask *mask_source; |
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| 134 | |
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| 135 | if (x0 < render->x0) |
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| 136 | { |
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| 137 | mask_buf += render->x0 - x0; |
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| 138 | x0 = render->x0; |
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| 139 | } |
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| 140 | if (x1 > render->x1) |
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| 141 | x1 = render->x1; |
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| 142 | |
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| 143 | if (y0 < render->y0) |
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| 144 | { |
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| 145 | mask_buf += (render->y0 - y0) * rowstride; |
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| 146 | y0 = render->y0; |
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| 147 | } |
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| 148 | if (y1 > render->y1) |
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| 149 | y1 = render->y1; |
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| 150 | |
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| 151 | mask_source = art_new (ArtMaskSourceMask, 1); |
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| 152 | |
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| 153 | mask_source->super.super.render = NULL; |
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| 154 | mask_source->super.super.done = art_render_mask_done; |
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| 155 | mask_source->super.can_drive = art_render_mask_can_drive; |
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| 156 | mask_source->super.invoke_driver = NULL; |
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| 157 | mask_source->super.prepare = art_render_mask_prepare; |
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| 158 | mask_source->render = render; |
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| 159 | mask_source->x0 = x0; |
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| 160 | mask_source->y0 = y0; |
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| 161 | mask_source->x1 = x1; |
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| 162 | mask_source->y1 = y1; |
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| 163 | mask_source->mask_buf = mask_buf; |
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| 164 | mask_source->rowstride = rowstride; |
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| 165 | |
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| 166 | art_render_add_mask_source (render, &mask_source->super); |
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| 167 | |
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| 168 | } |
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