GUI: Simplify WML message dialog formulas

Now with 99% less WML macros inserted into the formula.
This makes it easier to read and possibly even more efficient.

data/gui/default/window/wml_message.cfg

@@ -5,66 +5,40 @@
 ### window definitions. So this unit is a bit larger as wanted.
 ###
 
-# These might become global have to evaluate later.
-#define _GUI_HEIGHT_OFFSET
-	25#enddef
-
-# helper convert the scale factor, since we use it in two places define it as
-# helper value. (Two the not working and working version, but want to avoid
-# surprises when the not working version is fixed).
-#define __GUI_SIZE_FACTOR
-	3#enddef
-
-### The formula language doesn't support variables so macros are used to
-### emulate them. This makes the code what harder to read, so the algorithm for
-### __GUI_IMAGE_WIDTH is described here:
-###
-### if gamemap_width <= TEXT_WIDTH_SATURATION
-###     __GUI_IMAGE_WIDTH = gamemap_width / 3
-### else
-###     # Text reached it maximum width, take all space.
-###     __GUI_IMAGE_WIDTH = gamemap_width - MAX_TEXT_WIDTH
-### fi
-###
-### if __GUI_IMAGE_WIDTH < 250
-###     __GUI_IMAGE_WIDTH = 250
-### fi
-###
-### if __GUI_IMAGE_WIDTH > 500
-###     __GUI_IMAGE_WIDTH = 500
-### fi
-
-#define __GUI_MAX_HEIGHT
-(gamemap_height - 4)
-#enddef
-
 # The maximum width of the text
 #define MAX_TEXT_WIDTH
 675
 #enddef
 
-# gamemap_width width needed to reach the MAX_TEXT_WIDTH
-#define TEXT_WIDTH_SATURATION
-((3 * {_GUI_HEIGHT_OFFSET}) / 2)
-#enddef
-
-#define BEST_WIDTH
-(if(gamemap_width > {TEXT_WIDTH_SATURATION}, gamemap_width - {MAX_TEXT_WIDTH}, (gamemap_width / {__GUI_SIZE_FACTOR})))
-#enddef
-
-#define ASPECT_RATIO
-(if(image_original_width > 0, (as_decimal(image_original_height) / image_original_width), 0)) 
-#enddef
-
-#define __GUI_BEST_SIZE
-(if(({BEST_WIDTH} * {ASPECT_RATIO}) > {__GUI_MAX_HEIGHT}, floor({__GUI_MAX_HEIGHT} / {ASPECT_RATIO}), {BEST_WIDTH}))
-#enddef
-
 #define ___GUI_IMAGE_WIDTH
-	if({__GUI_BEST_SIZE} < 250, 250,
-		if({__GUI_BEST_SIZE} > 500, 500, {__GUI_BEST_SIZE})
+(
+	max(250, min(500, best_size))
+where
+	best_size = (
+		if((best_width * aspect_ratio) > max_height,
+			floor(max_height / aspect_ratio),
+			best_width
+		)
+	where
+		best_width = (
+			if(gamemap_width > text_width_saturation,
+				gamemap_width - {MAX_TEXT_WIDTH},
+				gamemap_width / size_factor
+			)
+		where
+			# gamemap_width width needed to reach the MAX_TEXT_WIDTH #
+			text_width_saturation = 3 * height_offset / 2 where height_offset = 25,
+			size_factor = 3
+		),
+		aspect_ratio = (
+			if(image_original_width > 0,
+				as_decimal(image_original_height) / image_original_width,
+				0
+			)
+		),
+		max_height = (gamemap_height - 4)
 	)
-#enddef
+)#enddef
 
 # This is the version with debug info
 #define __GUI_IMAGE_WIDTH
@@ -75,10 +49,6 @@
 	debug_print('gamemap_height ', gamemap_height),
 	debug_print('image_original_width ', image_original_width),
 	debug_print('image_original_height ', image_original_height),
-	debug_print('ASPECT_RATIO ', {ASPECT_RATIO}),
-	debug_print('__GUI_MAX_HEIGHT ', {__GUI_MAX_HEIGHT}),
-	debug_print('BEST_WIDTH ', {BEST_WIDTH}),
-	debug_print('__GUI_BEST_SIZE ', {__GUI_BEST_SIZE})
 ],
 	{___GUI_IMAGE_WIDTH}
 ][1]
@@ -110,7 +80,9 @@
 (
 	if((image_original_width < 300) and (image_original_height < 300),
 		image_original_width,
-		((image_original_width * {__GUI_IMAGE_WIDTH}) / 500))
+		((image_original_width * calculated_width) / 500)
+	)
+where calculated_width = {__GUI_IMAGE_WIDTH}
 )#enddef
 
 # The formula to set the heighte of the real image height depending on the
@@ -119,16 +91,19 @@
 (
 	if((image_original_width < 300) and (image_original_height < 300),
 		image_original_height,
-		((image_original_height * {__GUI_IMAGE_WIDTH}) / 500))
+		((image_original_height * calculated_width) / 500)
+	)
+where calculated_width = {__GUI_IMAGE_WIDTH}
 )#enddef
 
 # The X location of the image to display, only tested on the left side.
-#define __GUI_IMAGE_DISPLAYED_X X
+#define __GUI_IMAGE_DISPLAYED_X
 (
 	if(image_original_width > 100,
-		{X},
-		({__GUI_IMAGE_WIDTH} - image_width) / 2)
-
+		0,
+		(calculated_width - image_width) / 2
+	)
+where calculated_width = {__GUI_IMAGE_WIDTH}
 )#enddef
 
 # The Y location of the image to display, only tested on the left side.
@@ -142,8 +117,9 @@
 (
 	if(image_original_height > 0,
 		(height - image_height),
-		height - (({__GUI_IMAGE_WIDTH} - image_height) / 2))
-
+		height - ((calculated_width - image_height) / 2)
+	)
+where calculated_width = {__GUI_IMAGE_WIDTH}
 )#enddef
 
 [window_definition]
@@ -165,7 +141,7 @@
 			[draw]
 
 				[image]
-					x = "{__GUI_IMAGE_DISPLAYED_X X}"
+					x = "{__GUI_IMAGE_DISPLAYED_X}"
 					y = "{__GUI_IMAGE_DISPLAYED_Y}"
 					w = "{__GUI_IMAGE_DISPLAYED_WIDTH}"
 					h = "{__GUI_IMAGE_DISPLAYED_HEIGHT}"
@@ -780,8 +756,4 @@ if(gamemap_width - (10 + ({__GUI_IMAGE_WIDTH})) > {MAX_TEXT_WIDTH}
 #undef _GUI_IMAGE_WIDTH
 #undef __GUI_IMAGE_WIDTH
 #undef ___GUI_IMAGE_WIDTH
-#undef __GUI_BEST_SIZE
-#undef __GUI_MAX_HEIGHT
-#undef __GUI_SIZE_FACTOR
-#undef _GUI_HEIGHT_OFFSET
-
+#undef MAX_TEXT_WIDTH