SDL  2.0
SDL_drawline.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 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_internal.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: */
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
GLuint GLfloat GLfloat GLfloat x1
GLenum GLenum dst
GLint GLint GLint GLint GLint x
Definition: SDL_opengl.h:1574
Uint8 BytesPerPixel
Definition: SDL_pixels.h:320
#define BLINE(x1, y1, x2, y2, op, draw_end)
Definition: SDL_draw.h:375
GLuint GLuint GLsizei count
Definition: SDL_opengl.h:1571
#define DRAW_FASTSETPIXELXY1(x, y)
Definition: SDL_draw.h:42
#define DRAW_FASTSETPIXELXY4(x, y)
Definition: SDL_draw.h:44
GLfixed GLfixed GLfixed y2
#define DRAW_SETPIXELXY2_BLEND_RGB(x, y)
Definition: SDL_draw.h:239
#define VLINE(type, op, draw_end)
Definition: SDL_draw.h:318
The structure that defines a point.
Definition: SDL_rect.h:48
A collection of pixels used in software blitting.
Definition: SDL_surface.h:69
#define DLINE(type, op, draw_end)
Definition: SDL_draw.h:340
#define HLINE(type, op, draw_end)
Definition: SDL_draw.h:296
uint32_t Uint32
Definition: SDL_stdinc.h:181
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
GLfixed GLfixed x2
void(* DrawLineFunc)(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, SDL_bool draw_end)
Definition: SDL_drawline.c:120
GLfixed GLfixed GLint GLint GLfixed points
GLfixed y1
int x
Definition: SDL_rect.h:50
#define DRAW_FASTSETPIXEL1
Definition: SDL_draw.h:34
int y
Definition: SDL_rect.h:51
void * pixels
Definition: SDL_surface.h:75
uint8_t Uint8
Definition: SDL_stdinc.h:157
#define DRAW_SETPIXELXY_BLEND_RGB888(x, y)
Definition: SDL_draw.h:174
Uint8 BitsPerPixel
Definition: SDL_pixels.h:319
#define DRAW_SETPIXELXY_BLEND_RGB555(x, y)
Definition: SDL_draw.h:112
GLint GLint GLint GLint GLint GLint y
Definition: SDL_opengl.h:1574
#define DRAW_SETPIXELXY4_BLEND_RGB(x, y)
Definition: SDL_draw.h:242
#define SDL_GetRGBA
SDL_Rect clip_rect
Definition: SDL_surface.h:85
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:50
#define DRAW_FASTSETPIXEL4
Definition: SDL_draw.h:36
#define NULL
Definition: begin_code.h:164
SDL_bool
Definition: SDL_stdinc.h:139
#define DRAW_FASTSETPIXELXY2(x, y)
Definition: SDL_draw.h:43
SDL_PixelFormat * format
Definition: SDL_surface.h:72
#define SDL_SetError
GLenum func
#define AALINE(x1, y1, x2, y2, opaque_op, blend_op, draw_end)
Definition: SDL_draw.h:547
SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char const char SDL_SCANF_FORMAT_STRING const char return SDL_ThreadFunction const char void return Uint32 return Uint32 void
GLuint color
static DrawLineFunc SDL_CalculateDrawLineFunc(const SDL_PixelFormat *fmt)
Definition: SDL_drawline.c:125
uint16_t Uint16
Definition: SDL_stdinc.h:169
#define DRAW_SETPIXELXY_BLEND_RGB565(x, y)
Definition: SDL_draw.h:143
#define ABS(_x)
Definition: SDL_draw.h:293
#define DRAW_FASTSETPIXEL2
Definition: SDL_draw.h:35
int SDL_DrawLine(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color)
Definition: SDL_drawline.c:142
#define SDL_IntersectRectAndLine
GLuint GLsizei GLsizei * length
#define DRAW_SETPIXELXY_BLEND_ARGB8888(x, y)
Definition: SDL_draw.h:205
int SDL_DrawPoint(SDL_Surface *dst, int x, int y, Uint32 color)
Definition: SDL_drawpoint.c:30
#define SDL_memset
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