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SDL_drawline.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "SDL_config.h"
22 
23 #if !SDL_RENDER_DISABLED
24 
25 #include "SDL_draw.h"
26 #include "SDL_drawline.h"
27 #include "SDL_drawpoint.h"
28 
29 
30 static void
31 SDL_DrawLine1(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
32  SDL_bool draw_end)
33 {
34  if (y1 == y2) {
35  int length;
36  int pitch = (dst->pitch / dst->format->BytesPerPixel);
37  Uint8 *pixel;
38  if (x1 <= x2) {
39  pixel = (Uint8 *)dst->pixels + y1 * pitch + x1;
40  length = draw_end ? (x2-x1+1) : (x2-x1);
41  } else {
42  pixel = (Uint8 *)dst->pixels + y1 * pitch + x2;
43  if (!draw_end) {
44  ++pixel;
45  }
46  length = draw_end ? (x1-x2+1) : (x1-x2);
47  }
48  SDL_memset(pixel, color, length);
49  } else if (x1 == x2) {
50  VLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);
51  } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
52  DLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);
53  } else {
54  BLINE(x1, y1, x2, y2, DRAW_FASTSETPIXELXY1, draw_end);
55  }
56 }
57 
58 static void
59 SDL_DrawLine2(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
60  SDL_bool draw_end)
61 {
62  if (y1 == y2) {
63  HLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
64  } else if (x1 == x2) {
65  VLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
66  } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
67  DLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);
68  } else {
69  Uint8 _r, _g, _b, _a;
70  const SDL_PixelFormat * fmt = dst->format;
71  SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);
72  if (fmt->Rmask == 0x7C00) {
73  AALINE(x1, y1, x2, y2,
75  draw_end);
76  } else if (fmt->Rmask == 0xF800) {
77  AALINE(x1, y1, x2, y2,
79  draw_end);
80  } else {
81  AALINE(x1, y1, x2, y2,
83  draw_end);
84  }
85  }
86 }
87 
88 static void
89 SDL_DrawLine4(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,
90  SDL_bool draw_end)
91 {
92  if (y1 == y2) {
93  HLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
94  } else if (x1 == x2) {
95  VLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
96  } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
97  DLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);
98  } else {
99  Uint8 _r, _g, _b, _a;
100  const SDL_PixelFormat * fmt = dst->format;
101  SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);
102  if (fmt->Rmask == 0x00FF0000) {
103  if (!fmt->Amask) {
104  AALINE(x1, y1, x2, y2,
106  draw_end);
107  } else {
108  AALINE(x1, y1, x2, y2,
110  draw_end);
111  }
112  } else {
113  AALINE(x1, y1, x2, y2,
115  draw_end);
116  }
117  }
118 }
119 
121  int x1, int y1, int x2, int y2,
122  Uint32 color, SDL_bool draw_end);
123 
124 static DrawLineFunc
126 {
127  switch (fmt->BytesPerPixel) {
128  case 1:
129  if (fmt->BitsPerPixel < 8) {
130  break;
131  }
132  return SDL_DrawLine1;
133  case 2:
134  return SDL_DrawLine2;
135  case 4:
136  return SDL_DrawLine4;
137  }
138  return NULL;
139 }
140 
141 int
142 SDL_DrawLine(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color)
143 {
145 
146  if (!dst) {
147  return SDL_SetError("SDL_DrawLine(): Passed NULL destination surface");
148  }
149 
150  func = SDL_CalculateDrawLineFunc(dst->format);
151  if (!func) {
152  return SDL_SetError("SDL_DrawLine(): Unsupported surface format");
153  }
154 
155  /* Perform clipping */
156  /* FIXME: We don't actually want to clip, as it may change line slope */
157  if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {
158  return 0;
159  }
160 
161  func(dst, x1, y1, x2, y2, color, SDL_TRUE);
162  return 0;
163 }
164 
165 int
167  Uint32 color)
168 {
169  int i;
170  int x1, y1;
171  int x2, y2;
172  SDL_bool draw_end;
174 
175  if (!dst) {
176  return SDL_SetError("SDL_DrawLines(): Passed NULL destination surface");
177  }
178 
179  func = SDL_CalculateDrawLineFunc(dst->format);
180  if (!func) {
181  return SDL_SetError("SDL_DrawLines(): Unsupported surface format");
182  }
183 
184  for (i = 1; i < count; ++i) {
185  x1 = points[i-1].x;
186  y1 = points[i-1].y;
187  x2 = points[i].x;
188  y2 = points[i].y;
189 
190  /* Perform clipping */
191  /* FIXME: We don't actually want to clip, as it may change line slope */
192  if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {
193  continue;
194  }
195 
196  /* Draw the end if it was clipped */
197  draw_end = (x2 != points[i].x || y2 != points[i].y);
198 
199  func(dst, x1, y1, x2, y2, color, draw_end);
200  }
201  if (points[0].x != points[count-1].x || points[0].y != points[count-1].y) {
202  SDL_DrawPoint(dst, points[count-1].x, points[count-1].y, color);
203  }
204  return 0;
205 }
206 
207 #endif /* !SDL_RENDER_DISABLED */
208 
209 /* vi: set ts=4 sw=4 expandtab: */
DECLSPEC SDL_bool SDLCALL SDL_IntersectRectAndLine(const SDL_Rect *rect, int *X1, int *Y1, int *X2, int *Y2)
Calculate the intersection of a rectangle and line segment.
Definition: SDL_rect.c:316
int SDL_DrawLines(SDL_Surface *dst, const SDL_Point *points, int count, Uint32 color)
Definition: SDL_drawline.c:166
static void SDL_DrawLine4(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, SDL_bool draw_end)
Definition: SDL_drawline.c:89
GLvoid **typedef void(GLAPIENTRY *PFNGLGETVERTEXATTRIBDVPROC)(GLuint
Definition: glew.h:1824
GLuint color
Definition: glew.h:7185
#define NULL
Definition: ftobjs.h:61
Uint8 BytesPerPixel
Definition: SDL_pixels.h:277
#define BLINE(x1, y1, x2, y2, op, draw_end)
Definition: SDL_draw.h:374
SDL_bool
Definition: SDL_stdinc.h:116
#define DRAW_FASTSETPIXELXY1(x, y)
Definition: SDL_draw.h:42
#define DRAW_FASTSETPIXELXY4(x, y)
Definition: SDL_draw.h:44
#define DRAW_SETPIXELXY2_BLEND_RGB(x, y)
Definition: SDL_draw.h:238
#define VLINE(type, op, draw_end)
Definition: SDL_draw.h:317
EGLSurface EGLint x
Definition: eglext.h:293
The structure that defines a point.
Definition: SDL_rect.h:47
A collection of pixels used in software blitting.
Definition: SDL_surface.h:69
void(* DrawLineFunc)(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, SDL_bool draw_end)
Definition: SDL_drawline.c:120
#define ABS(_x)
#define DLINE(type, op, draw_end)
Definition: SDL_draw.h:339
#define HLINE(type, op, draw_end)
Definition: SDL_draw.h:295
if(!yyg->yy_init)
GLenum func
Definition: SDL_opengl.h:5654
GLuint GLfloat GLfloat GLfloat GLfloat y1
Definition: glew.h:11582
GLfixed GLfixed GLfixed y2
Definition: glext.h:4559
static void SDL_DrawLine2(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, SDL_bool draw_end)
Definition: SDL_drawline.c:59
uint32_t Uint32
An unsigned 32-bit integer type.
Definition: SDL_stdinc.h:145
int x
Definition: SDL_rect.h:49
#define DRAW_FASTSETPIXEL1
Definition: SDL_draw.h:34
GLenum GLenum dst
Definition: glew.h:2396
GLsizei GLsizei * length
Definition: gl2ext.h:792
int y
Definition: SDL_rect.h:50
void * pixels
Definition: SDL_surface.h:75
#define DRAW_SETPIXELXY_BLEND_RGB888(x, y)
Definition: SDL_draw.h:173
Uint8 BitsPerPixel
Definition: SDL_pixels.h:276
GLint GLsizei count
Definition: gl2ext.h:1011
#define DRAW_SETPIXELXY_BLEND_RGB555(x, y)
Definition: SDL_draw.h:111
DECLSPEC void *SDLCALL SDL_memset(void *dst, int c, size_t len)
Definition: SDL_string.c:261
DECLSPEC int SDLCALL SDL_SetError(const char *fmt,...)
Definition: SDL_error.c:53
#define DRAW_SETPIXELXY4_BLEND_RGB(x, y)
Definition: SDL_draw.h:241
SDL_Rect clip_rect
Definition: SDL_surface.h:85
GLuint GLfloat GLfloat GLfloat x1
Definition: glew.h:11582
#define DRAW_FASTSETPIXEL4
Definition: SDL_draw.h:36
EGLSurface EGLint EGLint y
Definition: eglext.h:293
#define DRAW_FASTSETPIXELXY2(x, y)
Definition: SDL_draw.h:43
SDL_PixelFormat * format
Definition: SDL_surface.h:72
DECLSPEC void SDLCALL SDL_GetRGBA(Uint32 pixel, const SDL_PixelFormat *format, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a)
Get the RGBA components from a pixel of the specified format.
Definition: SDL_pixels.c:849
#define AALINE(x1, y1, x2, y2, opaque_op, blend_op, draw_end)
Definition: SDL_draw.h:546
uint8_t Uint8
An unsigned 8-bit integer type.
Definition: SDL_stdinc.h:129
GLfixed GLfixed x2
Definition: glext.h:4559
static DrawLineFunc SDL_CalculateDrawLineFunc(const SDL_PixelFormat *fmt)
Definition: SDL_drawline.c:125
uint16_t Uint16
An unsigned 16-bit integer type.
Definition: SDL_stdinc.h:137
GLuint GLdouble GLdouble GLint GLint const GLdouble * points
Definition: glew.h:3337
#define DRAW_SETPIXELXY_BLEND_RGB565(x, y)
Definition: SDL_draw.h:142
#define DRAW_FASTSETPIXEL2
Definition: SDL_draw.h:35
int i
Definition: pngrutil.c:1377
int SDL_DrawLine(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color)
Definition: SDL_drawline.c:142
#define DRAW_SETPIXELXY_BLEND_ARGB8888(x, y)
Definition: SDL_draw.h:204
int SDL_DrawPoint(SDL_Surface *dst, int x, int y, Uint32 color)
Definition: SDL_drawpoint.c:30
static void SDL_DrawLine1(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, SDL_bool draw_end)
Definition: SDL_drawline.c:31