ref: fdf4c12f78354d0886bc1ff29f7605bb671f4a91
parent: 20462b4b4afbc56235201903221a1fb15f14d605
author: phil9 <telephil9@gmail.com>
date: Mon Dec 5 14:38:23 EST 2022
implement lerpColor()
--- a/api.c
+++ b/api.c
@@ -143,6 +143,32 @@
return 0;
}
+void
+checkcolor(lua_State *L, int index, int *r, int *g, int *b)
+{+ lua_pushstring(L, "r");
+ lua_gettable(L, index);
+ *r = luaL_checkinteger(L, -1);
+ lua_pushstring(L, "g");
+ lua_gettable(L, index);
+ *g = luaL_checkinteger(L, -1);
+ lua_pushstring(L, "b");
+ lua_gettable(L, index);
+ *b = luaL_checkinteger(L, -1);
+}
+
+void
+pushcolor(lua_State *L, int r, int g, int b)
+{+ lua_newtable(L);
+ lua_pushinteger(L, r);
+ lua_setfield(L, -2, "r");
+ lua_pushinteger(L, g);
+ lua_setfield(L, -2, "g");
+ lua_pushinteger(L, b);
+ lua_setfield(L, -2, "b");
+}
+
Image*
getcolor(lua_State *L)
{@@ -151,21 +177,10 @@
c = lua_gettop(L);
if(c == 1){- if(lua_istable(L, 1)){- lua_pushstring(L, "r");
- lua_gettable(L, 1);
- r = luaL_checkinteger(L, -1);
- lua_pushstring(L, "g");
- lua_gettable(L, 1);
- g = luaL_checkinteger(L, -1);
- lua_pushstring(L, "b");
- lua_gettable(L, 1);
- b = luaL_checkinteger(L, -1);
- }else{- r = luaL_checkinteger(L, 1);
- g = r;
- b = r;
- }
+ if(lua_istable(L, 1))
+ checkcolor(L, 1, &r, &g, &b);
+ else
+ r = g = b = luaL_checkinteger(L, 1);
i = color(r, g, b, 0);
}else if(c == 3){r = luaL_checkinteger(L, 1);
@@ -571,17 +586,30 @@
b = luaL_checkinteger(L, 3);
if(colormode == Chsv)
hsvtorgb(r, g, b, &r, &g, &b);
- lua_newtable(L);
- lua_pushinteger(L, r);
- lua_setfield(L, -2, "r");
- lua_pushinteger(L, g);
- lua_setfield(L, -2, "g");
- lua_pushinteger(L, b);
- lua_setfield(L, -2, "b");
+ pushcolor(L, r, g, b);
return 1;
}
+int
+clerpcolor(lua_State *L)
+{+ int r0, g0, b0, r1, g1, b1, r, g, b;
+ double f;
+ checkcolor(L, 1, &r0, &g0, &b0);
+ checkcolor(L, 2, &r1, &g1, &b1);
+ f = luaL_checknumber(L, 3);
+ if(f < 0.0)
+ f = 0.0;
+ else if(f > 1.0)
+ f = 1.0;
+ r = f * (r1 - r0) + r0;
+ g = f * (g1 - g0) + g0;
+ b = f * (b1 - b0) + b0;
+ pushcolor(L, r, g, b);
+ return 1;
+}
+
int
cloadpixels(lua_State *L)
{@@ -678,6 +706,7 @@
registerfunc(L, "push", cpush);
registerfunc(L, "pop", cpop);
registerfunc(L, "color", ccolor);
+ registerfunc(L, "lerpColor", clerpcolor);
registerfunc(L, "loadPixels", cloadpixels);
registerfunc(L, "updatePixels", cupdatepixels);
registerfunc(L, "randomGaussian", crandomgaussian);
--- /dev/null
+++ b/samples/lerpcolor.lua
@@ -1,0 +1,23 @@
+#!/bin/slug
+
+function setup()
+ size(400,400)
+ background(51)
+ stroke(255)
+ from = color(204, 102, 0)
+ to = color(0, 102, 153)
+ interA = lerpColor(from, to, .33)
+ interB = lerpColor(from, to, .66)
+ fill(from)
+ rect(40, 80, 80, 240)
+ fill(interA)
+ rect(120, 80, 80, 240)
+ fill(interB)
+ rect(200, 80, 80, 240)
+ fill(to)
+ rect(280, 80, 80, 240)
+end
+
+function draw()
+end
+
--- a/slug.man
+++ b/slug.man
@@ -96,6 +96,17 @@
\f5color(\f2v1\fP, \f2v2\fP, \f2v3\fP)
Creates a color object which is an lua table with r, g, and b fields.
The parameters are affected by the current color mode, meaning they will be interpreted as either RGB or HSB.
+.TP
+\f5lerpColor(\f2c1\fP, \f2c2\fP, \f2amt\fP)
+Compute a
+.I color
+by interpolating colors
+.I c1
+and
+.I c2
+linearly by
+.I amt
+\&.
.SS Image
.TP
\f5pixels[]