progs/egl/openvg/trivial/star-oddeven.c

   1 #include "eglcommon.h"
   2
   3 #include <VG/openvg.h>
   4
   5 const VGfloat white_color[4] = {1.0, 1.0, 1.0, 1.0};
   6 const VGfloat green_color[4] = {0.0, 1.0, 0.0, 0.8};
   7 const VGfloat black_color[4] = {0.0, 0.0, 0.0, 1.0};
   8
   9 VGPath path;
  10 VGPaint fill;
  11
  12
  13 static void draw_point(VGfloat x, VGfloat y)
  14 {
  15
  16    static const VGubyte cmds[] = {VG_MOVE_TO_ABS, VG_LINE_TO_ABS, VG_LINE_TO_ABS,
  17                                   VG_LINE_TO_ABS, VG_CLOSE_PATH};
  18    const VGfloat coords[]   = {  x - 2,  y - 2,
  19                                  x + 2,  y - 2,
  20                                  x + 2,  y + 2,
  21                                  x - 2,  y + 2};
  22    VGPath path;
  23    VGPaint fill;
  24
  25    path = vgCreatePath(VG_PATH_FORMAT_STANDARD, VG_PATH_DATATYPE_F, 1, 0, 0, 0,
  26                        VG_PATH_CAPABILITY_ALL);
  27    vgAppendPathData(path, 5, cmds, coords);
  28
  29    fill = vgCreatePaint();
  30    vgSetParameterfv(fill, VG_PAINT_COLOR, 4, black_color);
  31    vgSetPaint(fill, VG_FILL_PATH);
  32
  33    vgDrawPath(path, VG_FILL_PATH);
  34
  35    vgDestroyPath(path);
  36    vgDestroyPaint(fill);
  37 }
  38
  39 static void draw_marks(VGPath path)
  40 {
  41     VGfloat point[2], tangent[2];
  42     int i = 0;
  43
  44     for (i = 0; i < 1300; i += 50) {
  45         vgPointAlongPath(path, 0, 6, i,
  46                          point + 0, point + 1,
  47                          tangent + 0, tangent + 1);
  48         draw_point(point[0], point[1]);
  49     }
  50 }
  51
  52 static void
  53 init(void)
  54 {
  55    static const VGubyte cmds[6] = {VG_MOVE_TO_ABS, VG_LINE_TO_ABS, VG_LINE_TO_ABS, VG_LINE_TO_ABS,
  56                                    VG_LINE_TO_ABS, VG_CLOSE_PATH};
  57    static const VGfloat coords[]   = {  0,  200,
  58                                         300,  200,
  59                                         50,   0,
  60                                         150, 300,
  61                                         250,   0};
  62    path = vgCreatePath(VG_PATH_FORMAT_STANDARD, VG_PATH_DATATYPE_F, 1, 0, 0, 0,
  63                        VG_PATH_CAPABILITY_ALL);
  64    vgAppendPathData(path, 6, cmds, coords);
  65
  66    fill = vgCreatePaint();
  67    vgSetParameterfv(fill, VG_PAINT_COLOR, 4, green_color);
  68    vgSetPaint(fill, VG_FILL_PATH);
  69
  70    vgSetfv(VG_CLEAR_COLOR, 4, white_color);
  71 }
  72
  73 /* new window size or exposure */
  74 static void
  75 reshape(int w, int h)
  76 {
  77    vgLoadIdentity();
  78 }
  79
  80 static void
  81 draw(void)
  82 {
  83     VGfloat point[2], tangent[2];
  84     int i = 0;
  85
  86     vgClear(0, 0, window_width(), window_height());
  87
  88     vgSetPaint(fill, VG_FILL_PATH);
  89     vgDrawPath(path, VG_FILL_PATH);
  90
  91     draw_marks(path);
  92
  93
  94     vgFlush();
  95 }
  96
  97
  98 int main(int argc, char **argv)
  99 {
 100    return run(argc, argv, init, reshape,
 101               draw, 0);
 102 }