implement stroke operation

1 files changed, 27 insertions, 2 deletions

diff --git a/drawing/drawing.ha b/drawing/drawing.ha
index 063577d..a7d9e1f 100644
--- a/drawing/drawing.ha
+++ b/drawing/drawing.ha
@@ -1,8 +1,7 @@
-use sdl2;
 use fmt;
 use io;
 use endian;
-use math::random;
+use math;
 
 export def CHUNKSIZE = 512;
 
@@ -53,6 +52,8 @@ export fn outline_picture(pic: *picture) void = {
 
 fn min(a: i32, b: i32) i32 = if (a<b) a else b;
 fn max(a: i32, b: i32) i32 = if (a<b) b else a;
+fn sign(x: i32) i32 = if (x < 0) -1 else if (x > 0) 1 else 0;
+fn abs(x: i32) i32 = if (x<0) -x else x;
 
 // Draws a circle onto the picture, at given position radius color
 // Clips at the boundaries of the picture to avoid overflow.
@@ -98,6 +99,23 @@ export fn circle_hollow(picture: *picture, c: pos, r: i32, color: u32) void = {
 		};
 	};
 };
+
+export fn stroke(picture: *picture, c0: pos, c1: pos, r: i32, color: u32) void = {
+	const dx = c1.0 - c0.0;
+	const dy = c1.1 - c0.1;
+	const count = (abs(dx)+abs(dy))/r;
+	const sx = dx: f64 / (count-1): f64;
+	const sy = dy: f64 / (count-1): f64;
+
+	for (let i = 0i32; i < count; i += 1) {
+		const cx = c0.0 + math::roundf64(i:f64*sx):i32;
+		const cy = c0.1 + math::roundf64(i:f64*sy):i32;
+
+		circle(picture, (cx, cy), r, color);
+	};
+};
+
+// ehh should check bounding box instead of doing all pictures maybe
 export fn perform(pictures: []picture, op: op) void = {
 	match (op) {
 	case let o: op_circle =>
@@ -109,5 +127,12 @@ export fn perform(pictures: []picture, op: op) void = {
 				(x - pic.world_pos.0, y - pic.world_pos.1): pos;
 			circle(pic, pos_within_pic, r: i32, c);
 		};
+	case let s: op_stroke =>
+		const col = s.color & 0xffffff;
+		for (const pic &.. pictures) {
+			const c0 = (s.pos0.0 - pic.world_pos.0, s.pos0.1 - pic.world_pos.1);
+			const c1 = (s.pos1.0 - pic.world_pos.0, s.pos1.1 - pic.world_pos.1);
+			stroke(pic, c0, c1, s.radius: i32, col);
+		};
 	};
 };