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SDL_drawline.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2010 Sam Lantinga
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This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
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#include "SDL_draw.h"
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#include "SDL_drawline.h"
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static void
SDL_DrawLine1(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
SDL_bool draw_end)
{
if (y1 == y2) {
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//HLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);
int length;
int pitch = (dst->pitch / dst->format->BytesPerPixel);
Uint8 *pixel;
if (x1 <= x2) {
pixel = (Uint8 *)dst->pixels + y1 * pitch + x1;
length = draw_end ? (x2-x1+1) : (x2-x1);
} else {
pixel = (Uint8 *)dst->pixels + y1 * pitch + x2;
if (!draw_end) {
++pixel;
}
length = draw_end ? (x1-x2+1) : (x1-x2);
}
SDL_memset(pixel, color, length);
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} else if (x1 == x2) {
VLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);
} else if (ABS(x1 - x2) == ABS(y1 - y2)) {
DLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);
} else {
BLINE(x1, y1, x2, y2, DRAW_FASTSETPIXELXY1, draw_end);
}
}
static void
SDL_DrawLine2(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
SDL_bool draw_end)
{
if (y1 == y2) {
HLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
} else if (x1 == x2) {
VLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
} else if (ABS(x1 - x2) == ABS(y1 - y2)) {
DLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
} else {
Uint8 _r, _g, _b, _a;
const SDL_PixelFormat * fmt = dst->format;
SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);
if (fmt->Rmask == 0x7C00) {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB555,
draw_end);
} else if (fmt->Rmask == 0xF800) {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB565,
draw_end);
} else {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY2_BLEND_RGB,
draw_end);
}
}
}
static void
SDL_DrawLine4(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
SDL_bool draw_end)
{
if (y1 == y2) {
HLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
} else if (x1 == x2) {
VLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
} else if (ABS(x1 - x2) == ABS(y1 - y2)) {
DLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
} else {
Uint8 _r, _g, _b, _a;
const SDL_PixelFormat * fmt = dst->format;
SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);
if (fmt->Rmask == 0x00FF0000) {
if (!fmt->Amask) {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_RGB888,
draw_end);
} else {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_ARGB8888,
draw_end);
}
} else {
AALINE(x1, y1, x2, y2,
DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY4_BLEND_RGB,
draw_end);
}
}
}
typedef void (*DrawLineFunc) (SDL_Surface * dst,
int x1, int y1, int x2, int y2,
Uint32 color, SDL_bool draw_end);
static DrawLineFunc
SDL_CalculateDrawLineFunc(const SDL_PixelFormat * fmt)
{
switch (fmt->BytesPerPixel) {
case 1:
if (fmt->BitsPerPixel < 8) {
break;
}
return SDL_DrawLine1;
case 2:
return SDL_DrawLine2;
case 4:
return SDL_DrawLine4;
}
return NULL;
}
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int
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SDL_DrawLine(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color)
{
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DrawLineFunc func;
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SDL_SetError("SDL_DrawLine(): Passed NULL destination surface");
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return -1;
}
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func = SDL_CalculateDrawLineFunc(dst->format);
if (!func) {
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SDL_SetError("SDL_DrawLine(): Unsupported surface format");
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}
/* Perform clipping */
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/* FIXME: We don't actually want to clip, as it may change line slope */
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if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {
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}
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func(dst, x1, y1, x2, y2, color, SDL_TRUE);
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int
SDL_DrawLines(SDL_Surface * dst, const SDL_Point * points, int count,
Uint32 color)
{
int i;
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int x1, y1;
int x2, y2;
SDL_bool draw_end;
DrawLineFunc func;
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if (!dst) {
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SDL_SetError("SDL_DrawLines(): Passed NULL destination surface");
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return -1;
}
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func = SDL_CalculateDrawLineFunc(dst->format);
if (!func) {
SDL_SetError("SDL_DrawLines(): Unsupported surface format");
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return -1;
}
for (i = 1; i < count; ++i) {
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x1 = points[i-1].x;
y1 = points[i-1].y;
x2 = points[i].x;
y2 = points[i].y;
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/* Perform clipping */
/* FIXME: We don't actually want to clip, as it may change line slope */
if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {
continue;
}
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/* Draw the end if it was clipped */
draw_end = (x2 != points[i].x || y2 != points[i].y);
func(dst, x1, y1, x2, y2, color, draw_end);
}
if (points[0].x != points[count-1].x || points[0].y != points[count-1].y) {
SDL_DrawPoint(dst, points[count-1].x, points[count-1].y, color);
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}
return 0;
}
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/* vi: set ts=4 sw=4 expandtab: */