forked from KolibriOS/kolibrios
136 lines
3.3 KiB
C
136 lines
3.3 KiB
C
/*!
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\file Draw_Line.c
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\author Mario Palomo <mpalomo@ihman.com>
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\author Jose M. de la Huerga Fernández
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\author Pepe González Mora
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\date 05-2002
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free Foundation,
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Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#define SDL_DRAW_PUTPIXEL_BPP(A, B, C) \
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*(##A##(##B##(Uint8*)super->pixels + y*super->pitch + x*SDL_DRAW_BPP))=##C##;
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#if SDL_DRAW_BPP == 1
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#define SDL_DRAW_PUTPIXEL SDL_DRAW_PUTPIXEL_BPP(0+,0+,color)
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#elif SDL_DRAW_BPP == 2
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#define SDL_DRAW_PUTPIXEL SDL_DRAW_PUTPIXEL_BPP((Uint16*),0+,color)
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#elif SDL_DRAW_BPP == 3
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#define SDL_DRAW_PUTPIXEL \
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SDL_DRAW_PUTPIXEL_BPP(0+,1+,(Uint8)colorbyte1) \
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if (SDL_BYTEORDER == SDL_BIG_ENDIAN) { \
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SDL_DRAW_PUTPIXEL_BPP(0+,0+,(Uint8)colorbyte2) \
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SDL_DRAW_PUTPIXEL_BPP(0+,2+,(Uint8)colorbyte0) \
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}else{ \
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SDL_DRAW_PUTPIXEL_BPP(0+,0+,(Uint8)colorbyte0) \
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SDL_DRAW_PUTPIXEL_BPP(0+,2+,(Uint8)colorbyte2) \
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}
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#elif SDL_DRAW_BPP == 4
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#define SDL_DRAW_PUTPIXEL SDL_DRAW_PUTPIXEL_BPP((Uint32*),0+,color)
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#endif /*SDL_DRAW_BPP*/
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void SDL_DRAWFUNCTION(SDL_Surface *super,
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Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2,
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Uint32 color)
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{
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#if SDL_DRAW_BPP == 3
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Uint8 colorbyte0 = (Uint8) (color & 0xff);
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Uint8 colorbyte1 = (Uint8) ((color >> 8) & 0xff);
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Uint8 colorbyte2 = (Uint8) ((color >> 16) & 0xff);
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#endif
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Sint16 x = x1;
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Sint16 y = y1;
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Sint16 dy = y2 - y1;
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Sint16 dx = x2 - x1;
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Sint16 G, DeltaG1, DeltaG2, minG, maxG;
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Sint16 swap;
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Sint16 inc = 1;
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SDL_DRAW_PUTPIXEL
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if (abs(dy) < abs(dx)) { /* -1 < ramp < 1 */
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if (dx < 0) {
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dx = -dx;
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dy = -dy;
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swap = y2;
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y2 = y1;
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y1 = swap;
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swap = x2;
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x2 = x1;
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x1 = swap;
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}
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if (dy < 0) {
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dy = -dy;
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inc = -1;
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}
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G = 2 * dy - dx;
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DeltaG1 = 2 * (dy - dx);
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DeltaG2 = 2 * dy;
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while (x++ < x2) {
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if (G > 0) { G += DeltaG1; y += inc; }
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else G += DeltaG2;
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SDL_DRAW_PUTPIXEL
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}/*while*/
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} else { /* ramp < -1 or ramp > 1 */
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if (dy < 0) {
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dx = -dx;
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dy = -dy;
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swap = y2;
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y2 = y1;
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y1 = swap;
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swap = x2;
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x2 = x1;
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x1 = swap;
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}
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if (dx < 0) {
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dx = -dx;
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inc = -1;
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}
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G = 2 * dx - dy;
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minG = maxG = G;
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DeltaG1 = 2 * (dx - dy);
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DeltaG2 = 2 * dx;
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while (y++ < y2) {
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if (G > 0) { G += DeltaG1; x += inc; }
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else G += DeltaG2;
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SDL_DRAW_PUTPIXEL
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}/*while*/
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}/*if*/
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}/*Draw_Line*/
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#undef SDL_DRAW_PUTPIXEL
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#undef SDL_DRAW_PUTPIXEL_BPP
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