Added circle and ring drawing functions

example.lua

@@ -17,16 +17,16 @@ function tick(t)
     Draw.line(0xFFFF00FF,         8, 100, 100, 200, 100, 300, 600, 100, 100) --> { Vec2, ... }
 
     --        Color ARGB, thickness,   x,   y,   w,   h
-    Draw.rect(0xFFFF000F,         1, 100, 700, 320, 240) --> Rect
+    Draw.rect(0xFFFF000F,         4, 100, 700, 320, 240) --> Rect
     --             Color ARGB,   x,   y,   w,   h
     Draw.rect_fill(0xFF00FFFF, 100, 700, 320, 240) --> Rect
 
-    --[[
     --          Color ARGB, radius,   x,   y, start, end
-    Draw.circle(0xFFFF0000,     20, 300, 300) --> Rect
+    Draw.circle(0xFFFF0000,     40, 300, 300, t, t + math.pi / 2) --> Rect
     --        Color ARGB, outer, inner,  x,   y, start, end
-    Draw.ring(0xFF00FF00,    30,    20, 300, 300) --> Rect
+    Draw.ring(0xFFFFFFFF,    30,    20, 300, 300, t, t + math.pi) --> Rect
 
+    --[[
     --        font,            text, size,   x,   y, Color ARGB
     Draw.text(font, "Hello, world!",   32, 400, 400, 0xFFFF00FF) --> Rect
 

src/api_draw.c

@@ -3,6 +3,7 @@
 #include <cairo/cairo.h>
 #include <lua5.3/lua.h>
 #include <lua5.3/lauxlib.h>
+#include <math.h>
 
 int api_draw_clear(lua_State *L);
 int api_draw_pixel(lua_State *L);
@@ -10,6 +11,8 @@ int api_draw_line(lua_State *L);
 int api_draw_poly(lua_State *L);
 int api_draw_rect(lua_State *L);
 int api_draw_rect_fill(lua_State *L);
+int api_draw_circle(lua_State *L);
+int api_draw_ring(lua_State *L);
 
 bool loadapi_draw(lua_State *lua) {
   const struct luaL_Reg api_draw[] = {
@@ -19,6 +22,8 @@ bool loadapi_draw(lua_State *lua) {
     { "poly", api_draw_poly },
     { "rect", api_draw_rect },
     { "rect_fill", api_draw_rect_fill },
+    { "circle", api_draw_circle },
+    { "ring", api_draw_ring },
   };
   lua_newtable(lua);
   luaL_setfuncs(lua, api_draw, 0);
@@ -150,3 +155,56 @@ int api_draw_rect_fill(lua_State *L) {
   return 0;
 }
 
+int api_draw_circle(lua_State *L) {
+  cairo_t *cr = global_context.cairo_context.cairo;
+  int color = luaL_checkinteger(L, 1);
+  double a, r, g, b;
+  argb_to_cairo(color, &a, &r, &g, &b);
+
+  lua_Number radius = luaL_checknumber(L, 2);
+  lua_Number x = luaL_checknumber(L, 3);
+  lua_Number y = luaL_checknumber(L, 4);
+
+  lua_Number start = 0.0, end = M_PI * 2.0;
+  if (lua_gettop(L) > 4) {
+    start = luaL_checknumber(L, 5);
+    end = luaL_checknumber(L, 6);
+  }
+
+  cairo_set_source_rgba(cr, r, g, b, a);
+  cairo_move_to(cr, x, y);
+  cairo_arc(cr, x, y, radius, start, end);
+  cairo_fill(cr);
+  return 0;
+}
+
+int api_draw_ring(lua_State *L) {
+  cairo_t *cr = global_context.cairo_context.cairo;
+  int color = luaL_checkinteger(L, 1);
+  double a, r, g, b;
+  argb_to_cairo(color, &a, &r, &g, &b);
+
+  lua_Number outer = luaL_checknumber(L, 2);
+  lua_Number inner = luaL_checknumber(L, 3);
+  if (outer < inner) {
+    lua_Number tmp = outer;
+    outer = inner;
+    inner = tmp;
+  }
+
+  lua_Number x = luaL_checknumber(L, 4);
+  lua_Number y = luaL_checknumber(L, 5);
+
+  lua_Number start = 0.0, end = M_PI * 2.0;
+  if (lua_gettop(L) > 5) {
+    start = luaL_checknumber(L, 6);
+    end = luaL_checknumber(L, 7);
+  }
+
+  cairo_set_line_width(cr, outer - inner);
+  cairo_set_source_rgba(cr, r, g, b, a);
+  cairo_arc(cr, x, y, (outer + inner) / 2.0, start, end);
+  cairo_stroke(cr);
+
+  return 0;
+}