timage: allowed use of width/height keys for specific image size

data/gui/schema.cfg

@@ -1477,6 +1477,16 @@
                                     min="0"
                                     max="-1"
                                     super="generic/widget_instance"
+                                    [key]
+                                        name="width"
+                                        type="unsigned"
+                                        default=0
+                                    [/key]
+                                    [key]
+                                        name="height"
+                                        type="unsigned"
+                                        default=0
+                                    [/key]
                                 [/tag]
                                 [tag]
                                     name="instance"

data/gui/widget/image_default.cfg

@@ -24,6 +24,8 @@
 
 				[image]
 					name = "(text)"
+					w = "(width)"
+					h = "(height)"
 				[/image]
 
 			[/draw]

src/gui/widgets/image.cpp

@@ -49,6 +49,9 @@ tpoint timage::calculate_best_size() const
 	const tpoint maximum = get_config_maximum_size();
 
 	tpoint result = tpoint(image->w, image->h);
+	if(best_size_ != tpoint(0, 0)) {
+		result = best_size_;
+	}
 
 	if(minimum.x > 0 && result.x < minimum.x) {
 		DBG_GUI_L << LOG_HEADER << " increase width to minimum.\n";
@@ -162,7 +165,10 @@ timage_definition::tresolution::tresolution(const config& cfg)
 namespace implementation
 {
 
-tbuilder_image::tbuilder_image(const config& cfg) : tbuilder_control(cfg)
+tbuilder_image::tbuilder_image(const config& cfg)
+	: tbuilder_control(cfg)
+	, width(cfg["width"])
+	, height(cfg["height"])
 {
 }
 
@@ -172,6 +178,15 @@ twidget* tbuilder_image::build() const
 
 	init_control(widget);
 
+	const game_logic::map_formula_callable& size = get_screen_size_variables();
+
+	const unsigned w = width(size);
+	const unsigned h = height(size);
+
+	if(w || h) {
+		widget->set_best_size(tpoint(w, h));
+	}
+
 	DBG_GUI_G << "Window builder: placed image '" << id << "' with definition '"
 			  << definition << "'.\n";
 

src/gui/widgets/image.hpp

@@ -29,7 +29,7 @@ namespace gui2
 class timage : public tcontrol
 {
 public:
-	timage() : tcontrol(COUNT)
+	timage() : tcontrol(COUNT), best_size_(0, 0)
 	{
 	}
 
@@ -61,6 +61,11 @@ public:
 
 	virtual bool can_mouse_focus() const override { return !tooltip().empty(); }
 
+	void set_best_size(const tpoint& best_size)
+	{
+		best_size_ = best_size;
+	}
+
 	/***** ***** ***** ***** layout functions ***** ***** ***** *****/
 
 private:
@@ -93,6 +98,9 @@ private:
 		COUNT
 	};
 
+	/** When we're used as a fixed size item, this holds the best size. */
+	tpoint best_size_;
+
 	/** See @ref tcontrol::get_control_type. */
 	virtual const std::string& get_control_type() const override;
 };
@@ -120,6 +128,12 @@ struct tbuilder_image : public tbuilder_control
 
 	using tbuilder_control::build;
 
+	/** The width of the widget. */
+	tformula<unsigned> width;
+
+	/** The height of the widget. */
+	tformula<unsigned> height;
+
 	twidget* build() const;
 };