sdl/rect: Add scalar multiplication and division operators

Mostly useful for simplifying pixel scale conversions.

src/gui/core/canvas.cpp

@@ -461,16 +461,12 @@ void text_shape::draw(wfl::map_formula_callable& variables)
 	SDL_Rect visible = sdl::intersect_rects(draw::get_clip(), dst_rect);
 
 	// Get the source region of text for clipping.
-	SDL_Rect clip_in = visible;
+	rect clip_in = visible;
 	clip_in.x -= x;
 	clip_in.y -= y;
 
 	// Source region for high-dpi text needs to have pixel scale applied.
-	const int pixel_scale = CVideo::get_singleton().get_pixel_scale();
-	clip_in.x *= pixel_scale;
-	clip_in.y *= pixel_scale;
-	clip_in.w *= pixel_scale;
-	clip_in.h *= pixel_scale;
+	clip_in *= CVideo::get_singleton().get_pixel_scale();
 
 	// Render the currently visible portion of text
 	// TODO: highdpi - it would be better to render this all, but some things currently have far too much text. Namely the credits screen.

src/sdl/rect.hpp

@@ -122,6 +122,12 @@ public:
 	bool operator==(const rect& r) const;
 	bool operator==(const SDL_Rect& r) const;
 
+	// Scalar multiplication and division
+	rect operator*(int s) const { return {x*s, y*s, w*s, h*s}; }
+	rect& operator*=(int s) { x*=s; y*=s; w*=s; h*=s; return *this; }
+	rect operator/(int s) const { return {x/s, y/s, w/s, h/s}; }
+	rect& operator/=(int s) { x/=s; y/=s; w/=s; h/=s; return *this; }
+
 	/** False if both w and h are > 0, true otherwise. */
 	bool empty() const;
 };

src/video.cpp

@@ -528,10 +528,9 @@ SDL_Rect CVideo::clip_to_draw_area(const SDL_Rect* r) const
 	}
 }
 
-SDL_Rect CVideo::to_output(const SDL_Rect& r) const
+rect CVideo::to_output(const rect& r) const
 {
-	int s = get_pixel_scale();
-	return {s * r.x, s * r.y, s * r.w, s * r.h};
+	return r * get_pixel_scale();
 }
 
 void CVideo::render_screen()

src/video.hpp

@@ -19,6 +19,7 @@
 #include "exceptions.hpp"
 #include "lua_jailbreak_exception.hpp"
 #include "sdl/point.hpp"
+#include "sdl/rect.hpp"
 #include "sdl/texture.hpp"
 
 #include <SDL2/SDL_render.h>
@@ -198,7 +199,7 @@ public:
 	/**
 	 * Convert coordinates in draw space to coordinates in render space.
 	 */
-	SDL_Rect to_output(const SDL_Rect& draw_space_rect) const;
+	rect to_output(const rect& draw_space_rect) const;
 
 	/**
 	 * Tests whether the given flags are currently set on the SDL window.

src/widgets/textbox.cpp

@@ -184,7 +184,7 @@ void textbox::draw_contents()
 
 	draw::fill(loc, c);
 
-	SDL_Rect src;
+	rect src;
 
 	if(text_image_ == nullptr) {
 		update_text_cache(true);
@@ -227,8 +227,7 @@ void textbox::draw_contents()
 		}
 
 		// text may be rendered at high dpi, scale source clip accordingly
-		const int ps = video().get_pixel_scale();
-		src.x *= ps; src.y *= ps; src.w *= ps; src.h *= ps;
+		src *= video().get_pixel_scale();
 		// TODO: highdpi - consider sizing source clip in draw coordinates, now that textures have a draw-space w/h? That would work here.
 
 		if(enabled()) {