SDL 2.0
SDL_drawline.c
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1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2019 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
30static void
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
58static void
60 SDL_bool draw_end)
61{
62 if (y1 == y2) {
64 } else if (x1 == x2) {
66 } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
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
88static void
90 SDL_bool draw_end)
91{
92 if (y1 == y2) {
94 } else if (x1 == x2) {
96 } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
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
124static 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
141int
143{
145
146 if (!dst) {
147 return SDL_SetError("SDL_DrawLine(): Passed NULL destination surface");
148 }
149
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
165int
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
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) {
203 }
204 return 0;
205}
206
207#endif /* !SDL_RENDER_DISABLED */
208
209/* vi: set ts=4 sw=4 expandtab: */
#define HLINE(type, op, draw_end)
Definition: SDL_draw.h:296
#define DRAW_FASTSETPIXEL2
Definition: SDL_draw.h:35
#define DRAW_SETPIXELXY_BLEND_RGB888(x, y)
Definition: SDL_draw.h:174
#define DRAW_FASTSETPIXELXY4(x, y)
Definition: SDL_draw.h:44
#define DRAW_SETPIXELXY2_BLEND_RGB(x, y)
Definition: SDL_draw.h:239
#define AALINE(x1, y1, x2, y2, opaque_op, blend_op, draw_end)
Definition: SDL_draw.h:537
#define BLINE(x1, y1, x2, y2, op, draw_end)
Definition: SDL_draw.h:375
#define ABS(_x)
Definition: SDL_draw.h:293
#define DRAW_FASTSETPIXELXY2(x, y)
Definition: SDL_draw.h:43
#define DRAW_SETPIXELXY_BLEND_RGB565(x, y)
Definition: SDL_draw.h:143
#define DLINE(type, op, draw_end)
Definition: SDL_draw.h:340
#define DRAW_FASTSETPIXEL1
Definition: SDL_draw.h:34
#define DRAW_FASTSETPIXELXY1(x, y)
Definition: SDL_draw.h:42
#define DRAW_SETPIXELXY_BLEND_RGB555(x, y)
Definition: SDL_draw.h:112
#define DRAW_SETPIXELXY_BLEND_ARGB8888(x, y)
Definition: SDL_draw.h:205
#define DRAW_SETPIXELXY4_BLEND_RGB(x, y)
Definition: SDL_draw.h:242
#define DRAW_FASTSETPIXEL4
Definition: SDL_draw.h:36
#define VLINE(type, op, draw_end)
Definition: SDL_draw.h:318
int SDL_DrawLine(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color)
Definition: SDL_drawline.c:142
static DrawLineFunc SDL_CalculateDrawLineFunc(const SDL_PixelFormat *fmt)
Definition: SDL_drawline.c:125
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
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
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
void(* DrawLineFunc)(SDL_Surface *dst, int x1, int y1, int x2, int y2, Uint32 color, SDL_bool draw_end)
Definition: SDL_drawline.c:120
int SDL_DrawPoint(SDL_Surface *dst, int x, int y, Uint32 color)
Definition: SDL_drawpoint.c:30
#define SDL_SetError
#define SDL_memset
#define SDL_GetRGBA
#define SDL_IntersectRectAndLine
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
GLint GLint GLint GLint GLint GLint y
Definition: SDL_opengl.h:1574
GLuint GLuint GLsizei count
Definition: SDL_opengl.h:1571
GLint GLint GLint GLint GLint x
Definition: SDL_opengl.h:1574
GLfixed GLfixed GLint GLint GLfixed points
GLenum func
GLfixed GLfixed GLfixed y2
GLfixed y1
GLuint color
GLuint GLfloat GLfloat GLfloat x1
GLfixed GLfixed x2
GLenum GLenum dst
GLuint GLsizei GLsizei * length
SDL_bool
Definition: SDL_stdinc.h:162
@ SDL_TRUE
Definition: SDL_stdinc.h:164
uint32_t Uint32
Definition: SDL_stdinc.h:203
uint16_t Uint16
Definition: SDL_stdinc.h:191
uint8_t Uint8
Definition: SDL_stdinc.h:179
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 NULL
Definition: begin_code.h:167
Uint8 BytesPerPixel
Definition: SDL_pixels.h:320
Uint8 BitsPerPixel
Definition: SDL_pixels.h:319
The structure that defines a point (integer)
Definition: SDL_rect.h:49
A collection of pixels used in software blitting.
Definition: SDL_surface.h:71