Added padding

nasu6.c

@@ -1,6 +1,8 @@
 #include <SDL2/SDL.h>
 #include <stdio.h>
 
+#define PAD 32
+
 typedef struct Point {
 	int x;
 	int y;
@@ -21,8 +23,8 @@ typedef struct Brush {
 	Point prev;
 } Brush;
 
-static int SCREEN_WIDTH = 512;
-static int SCREEN_HEIGHT = 512;
+static int SCREEN_WIDTH = 512 + PAD * 2;
+static int SCREEN_HEIGHT = 512 + PAD * 2;
 static int FPS = 30;
 int ZOOM = 4;
 int clr = 0xFF0000;
@@ -51,14 +53,30 @@ divpt(Point* p, int v)
 	return p;
 }
 
+Point*
+mulpt(Point* p, int v)
+{
+	p->x *= v;
+	p->y *= v;
+	return p;
+}
+
+Point*
+addpt(Point* p, int v)
+{
+	p->x += v;
+	p->y += v;
+	return p;
+}
+
 /* noodle */
 
 void
 pixel(uint32_t* dst, Point p, int c)
 {
 	int x, y;
-	p.x *= ZOOM;
-	p.y *= ZOOM;
+	mulpt(&p, ZOOM);
+	addpt(&p, PAD);
 	for(x = 0; x < ZOOM; ++x) {
 		for(y = 0; y < ZOOM; ++y) {
 			dst[(p.y + y) * SCREEN_WIDTH + (p.x + x)] = c;
@@ -91,7 +109,7 @@ init_array(void)
 
 	for(i = 0; i < SCREEN_HEIGHT; i++)
 		for(j = 0; j < SCREEN_WIDTH; j++)
-			pixels[i * SCREEN_WIDTH + j] = 0xffffff;
+			pixels[i * SCREEN_WIDTH + j] = 0x000000;
 
 	return 1;
 }
@@ -160,6 +178,7 @@ handle_mouse(SDL_Event* event, Brush* b)
 	case SDL_MOUSEMOTION:
 		if(b->down) {
 			setpt(&b->pos, event->motion.x, event->motion.y);
+			addpt(&b->pos, -PAD);
 			divpt(&b->pos, ZOOM);
 			pixel(pixels, b->pos, 0xFFFFFF);
 			setpt(&b->prev, b->pos.x, b->pos.y);