Merge pull request #443 from markwheeler/screen-line-additions

Expose line_cap, line_join and miter_limit in screen.lua

lua/screen.lua

@@ -35,6 +35,24 @@ Screen.level = function(value) s_level(value) end
 -- @param w line width (in pixels, floats permitted)
 Screen.line_width = function(w) s_line_width(w) end
 
+--- set line cap style
+-- @param style line cap style string ("butt", "round" or "square"). default is "butt".
+Screen.line_cap = function(style)
+  s_line_cap(style)
+end
+
+--- set line join style
+-- @param style line join style string ("miter", "round" or "bevel"). default is "miter"
+Screen.line_join = function(style)
+  s_line_join(style)
+end
+
+--- set miter limit
+-- @param limit if the current line join style is set to "miter", the miter limit is used to determine whether the lines should be joined with a bevel instead of a miter. if the length of the miter divided by the line width is greater than the miter limit, the style is converted to a bevel. default value 10.
+Screen.miter_limit = function(limit)
+  s_miter_limit(limit)
+end
+
 --- move drawing position
 -- @param x position x
 -- @param y position y

matron/src/hardware/screen.c

@@ -242,6 +242,33 @@ void screen_line_width(double w) {
     cairo_set_line_width(cr,w);
 }
 
+void screen_line_cap(const char *style) {
+    CHECK_CR
+    if(strcmp(style, "round") == 0){
+      cairo_set_line_cap(cr,CAIRO_LINE_CAP_ROUND);
+    }else if(strcmp(style, "square") == 0){
+      cairo_set_line_cap(cr,CAIRO_LINE_CAP_SQUARE);
+    }else{
+      cairo_set_line_cap(cr,CAIRO_LINE_CAP_BUTT);
+    }
+}
+
+void screen_line_join(const char *style) {
+    CHECK_CR
+    if(strcmp(style, "round") == 0){
+      cairo_set_line_join(cr,CAIRO_LINE_JOIN_ROUND);
+    }else if(strcmp(style, "bevel") == 0){
+      cairo_set_line_join(cr,CAIRO_LINE_JOIN_BEVEL);
+    }else{
+      cairo_set_line_join(cr,CAIRO_LINE_JOIN_MITER);
+    }
+}
+
+void screen_miter_limit(double limit) {
+    CHECK_CR
+    cairo_set_miter_limit(cr,limit);
+}
+
 void screen_move(double x, double y) {
     CHECK_CR
     cairo_move_to(cr,x,y);

matron/src/hardware/screen.h

@@ -11,6 +11,9 @@ extern void screen_font_size(double z);
 extern void screen_aa(int s);
 extern void screen_level(int z);
 extern void screen_line_width(double w);
+extern void screen_line_cap(const char *style);
+extern void screen_line_join(const char *style);
+extern void screen_miter_limit(double limit);
 extern void screen_move(double x, double y);
 extern void screen_line(double x, double y);
 extern void screen_move_rel(double x, double y);

matron/src/weaver.c

@@ -70,6 +70,9 @@ static int _screen_font_size(lua_State *l);
 static int _screen_aa(lua_State *l);
 static int _screen_level(lua_State *l);
 static int _screen_line_width(lua_State *l);
+static int _screen_line_cap(lua_State *l);
+static int _screen_line_join(lua_State *l);
+static int _screen_miter_limit(lua_State *l);
 static int _screen_move(lua_State *l);
 static int _screen_line(lua_State *l);
 static int _screen_move_rel(lua_State *l);
@@ -199,6 +202,9 @@ void w_init(void) {
   lua_register(lvm, "s_aa", &_screen_aa);
   lua_register(lvm, "s_level", &_screen_level);
   lua_register(lvm, "s_line_width", &_screen_line_width);
+  lua_register(lvm, "s_line_cap", &_screen_line_cap);
+  lua_register(lvm, "s_line_join", &_screen_line_join);
+  lua_register(lvm, "s_miter_limit", &_screen_miter_limit);
   lua_register(lvm, "s_move", &_screen_move);
   lua_register(lvm, "s_line", &_screen_line);
   lua_register(lvm, "s_move_rel", &_screen_move_rel);
@@ -439,6 +445,54 @@ int _screen_line_width(lua_State *l) {
     return 0;
 }
 
+/***
+ * screen: set line cap
+ * @function s_line_cap
+ * @tparam string line cap style ("butt", "round" or "square"). default is "butt".
+ */
+int _screen_line_cap(lua_State *l) {
+  if (lua_gettop(l) != 1) {
+    return luaL_error(l, "wrong number of arguments");
+  }
+
+    const char *s = luaL_checkstring(l, 1);
+    screen_line_cap(s);
+    lua_settop(l, 0);
+    return 0;
+}
+
+/***
+ * screen: set line join
+ * @function s_line_join
+ * @tparam string line join style ("miter", "round" or "bevel"). default is "miter".
+ */
+int _screen_line_join(lua_State *l) {
+  if (lua_gettop(l) != 1) {
+    return luaL_error(l, "wrong number of arguments");
+  }
+
+    const char *s = luaL_checkstring(l, 1);
+    screen_line_join(s);
+    lua_settop(l, 0);
+    return 0;
+}
+
+/***
+ * screen: set miter limit
+ * @function s_miter_limit
+ * @tparam double miter limit
+ */
+int _screen_miter_limit(lua_State *l) {
+  if (lua_gettop(l) != 1) {
+    return luaL_error(l, "wrong number of arguments");
+  }
+
+    double limit = luaL_checknumber(l, 1);
+    screen_miter_limit(limit);
+    lua_settop(l, 0);
+    return 0;
+}
+
 /***
  * screen: move position
  * @function s_move