center draw

3 files changed, 37 insertions, 32 deletions

diff --git a/demo.c b/demo.c
index 7f49fb6..2bcbcde 100644
--- a/demo.c
+++ b/demo.c
@@ -11,9 +11,10 @@ int main(void)
 	LZR_ImageLoad("tset.bmp");
 	float darkness = 0.0f;
 	float dark_dir = 1.0f;
-	int x = 10;
-	int y = 20;
-	LZR_ImageDrawSettings stg = {0, 0, -1, -1, 1.0, 1.0, 0.0, false, false};
+	int x = 0;
+	int y = 0;
+	LZR_ImageDrawSettings stg = {0,   0,   -1,   -1,    1.0,
+	                             1.0, 0.0, true, false, false};
 	while (!LZR_ShouldQuit()) {
 		darkness += 0.01f * dark_dir;
 		if (darkness * dark_dir >= 0.5f) {
@@ -46,7 +47,7 @@ int main(void)
 		LZR_DrawTile(1, 4, 22, 2);
 		const float shade = 0.9 * (0.5f + darkness);
 		LZR_DrawSetColor(shade, shade, 0.0f);
-		LZR_DrawImageEx(0, x, y, &stg);
+		LZR_DrawImageEx(0, x, y, stg);
 		LZR_DrawEnd();
 	}
 	LZR_Quit();
diff --git a/lzr.c b/lzr.c
index 89fe573..9499f62 100644
--- a/lzr.c
+++ b/lzr.c
@@ -315,7 +315,7 @@ int LZR_DrawImage(int id, int x, int y)
 	return 0;
 }
 
-int LZR_DrawImageEx(int id, int x, int y, const LZR_ImageDrawSettings *stg)
+int LZR_DrawImageEx(int id, int x, int y, LZR_ImageDrawSettings stg)
 {
 	if (id < 0) {
 		dx_log_error("id is negative");
@@ -325,37 +325,41 @@ int LZR_DrawImageEx(int id, int x, int y, const LZR_ImageDrawSettings *stg)
 		dx_log_error("no image with id %d", id);
 		return -1;
 	}
-	const int width = (stg->width > 0) ? stg->width : images[id].width;
-	const int height = (stg->height > 0) ? stg->height : images[id].height;
-	SDL_Rect src = {stg->ix, stg->iy, width, height};
-	SDL_Rect dst = {x, y, width * stg->scale_x, height * stg->scale_y};
-	if (stg->ix < 0) {
-		src.w += stg->ix;
-		dst.x = 0 - stg->ix;
-		dst.w += stg->ix;
-	}
-	if (stg->iy < 0) {
-		src.y = 0 - stg->iy;
-		src.h += stg->iy;
-		dst.y -= stg->iy;
-		dst.h += stg->iy;
-	}
-	if (stg->ix + width > images[id].width) {
-		src.w = images[id].width - stg->ix;
-		dst.w = images[id].width - stg->ix;
-	}
-	if (stg->iy + height > images[id].height) {
-		src.h = images[id].height - stg->iy;
-		dst.h = images[id].height - stg->iy;
+	const int width = (stg.width > 0) ? stg.width : images[id].width;
+	const int height = (stg.height > 0) ? stg.height : images[id].height;
+	if (stg.center) {
+		x -= stg.scale_x * width / 2;
+		y -= stg.scale_y * height / 2;
+	}
+	SDL_Rect src = {stg.ix, stg.iy, width, height};
+	SDL_Rect dst = {x, y, width * stg.scale_x, height * stg.scale_y};
+	if (stg.ix < 0) {
+		src.w += stg.ix;
+		dst.x = 0 - stg.ix;
+		dst.w += stg.ix;
+	}
+	if (stg.iy < 0) {
+		src.y = 0 - stg.iy;
+		src.h += stg.iy;
+		dst.y -= stg.iy;
+		dst.h += stg.iy;
+	}
+	if (stg.ix + width > images[id].width) {
+		src.w = images[id].width - stg.ix;
+		dst.w = images[id].width - stg.ix;
+	}
+	if (stg.iy + height > images[id].height) {
+		src.h = images[id].height - stg.iy;
+		dst.h = images[id].height - stg.iy;
 	}
 	if (SDL_SetTextureColorMod(images[id].tex, color[0], color[1],
 	                           color[2]) < 0) {
 		dx_log_error("%s", SDL_GetError());
 		return -1;
 	}
-	const int flip = (stg->flip_h ? SDL_FLIP_VERTICAL : 0) |
-	                 (stg->flip_v ? SDL_FLIP_HORIZONTAL : 0);
-	if (SDL_RenderCopyEx(renderer, images[id].tex, &src, &dst, stg->angle,
+	const int flip = (stg.flip_h ? SDL_FLIP_VERTICAL : 0) |
+	                 (stg.flip_v ? SDL_FLIP_HORIZONTAL : 0);
+	if (SDL_RenderCopyEx(renderer, images[id].tex, &src, &dst, stg.angle,
 	                     NULL, flip)) {
 		dx_log_error("%s", SDL_GetError());
 		return -1;
diff --git a/lzr.h b/lzr.h
index 0aea47d..66c9ae5 100644
--- a/lzr.h
+++ b/lzr.h
@@ -36,7 +36,7 @@ typedef struct LZR_Event {
 typedef struct LZR_ImageDrawSettings {
 	int ix, iy, width, height;
 	double scale_x, scale_y, angle;
-	bool flip_v, flip_h;
+	bool center, flip_v, flip_h;
 } LZR_ImageDrawSettings;
 
 int LZR_Init(LZR_Config cfg);
@@ -54,7 +54,7 @@ int LZR_DrawPoint(int x, int y);
 int LZR_DrawLine(int x0, int y0, int x1, int y1);
 int LZR_DrawRect(bool fill, int x, int y, int w, int h);
 int LZR_DrawImage(int id, int x, int y);
-int LZR_DrawImageEx(int id, int x, int y, const LZR_ImageDrawSettings *stg);
+int LZR_DrawImageEx(int id, int x, int y, LZR_ImageDrawSettings stg);
 int LZR_DrawTile(int id, int tile, int x, int y);
 
 #endif