From ba94efba87955a3acd3fc1caa0ff6c9bdc70d767 Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter1138@openttd.org>
Date: Sun, 2 Oct 2022 19:34:22 +0100
Subject: [PATCH] Change: Add flag to apply resize to largest resize step
 first.

Resize step is normally allocated equally amongst all resizable widgets.
With this flag, we allocate as much as possible from the largest
resize step first.
---
 src/widget.cpp    | 44 ++++++++++++++++++++++++++++++++++++++++++--
 src/widget_type.h |  2 ++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/widget.cpp b/src/widget.cpp
index acc18b15e3..36c58748bf 100644
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -1356,7 +1356,7 @@ void NWidgetHorizontal::AssignSizePosition(SizingType sizing, uint x, uint y, ui
 	for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
 		uint hor_step = child_wid->GetHorizontalStepSize(sizing);
 		if (hor_step > 0) {
-			num_changing_childs++;
+			if (!(flags & NC_BIGFIRST)) num_changing_childs++;
 			biggest_stepsize = std::max(biggest_stepsize, hor_step);
 		} else {
 			child_wid->current_x = child_wid->smallest_x;
@@ -1366,6 +1366,16 @@ void NWidgetHorizontal::AssignSizePosition(SizingType sizing, uint x, uint y, ui
 		child_wid->current_y = ComputeMaxSize(child_wid->smallest_y, given_height - child_wid->padding_top - child_wid->padding_bottom, vert_step);
 	}
 
+	/* First.5 loop: count how many children are of the biggest step size. */
+	if ((flags & NC_BIGFIRST) && biggest_stepsize > 0) {
+		for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
+			uint hor_step = child_wid->GetHorizontalStepSize(sizing);
+			if (hor_step == biggest_stepsize) {
+				num_changing_childs++;
+			}
+		}
+	}
+
 	/* Second loop: Allocate the additional horizontal space over the resizing children, starting with the biggest resize steps. */
 	while (biggest_stepsize > 0) {
 		uint next_biggest_stepsize = 0;
@@ -1383,6 +1393,16 @@ void NWidgetHorizontal::AssignSizePosition(SizingType sizing, uint x, uint y, ui
 			next_biggest_stepsize = std::max(next_biggest_stepsize, hor_step);
 		}
 		biggest_stepsize = next_biggest_stepsize;
+
+		if (num_changing_childs == 0 && (flags & NC_BIGFIRST) && biggest_stepsize > 0) {
+			/* Second.5 loop: count how many children are of the updated biggest step size. */
+			for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
+				uint hor_step = child_wid->GetHorizontalStepSize(sizing);
+				if (hor_step == biggest_stepsize) {
+					num_changing_childs++;
+				}
+			}
+		}
 	}
 	assert(num_changing_childs == 0);
 
@@ -1512,7 +1532,7 @@ void NWidgetVertical::AssignSizePosition(SizingType sizing, uint x, uint y, uint
 	for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
 		uint vert_step = child_wid->GetVerticalStepSize(sizing);
 		if (vert_step > 0) {
-			num_changing_childs++;
+			if (!(flags & NC_BIGFIRST)) num_changing_childs++;
 			biggest_stepsize = std::max(biggest_stepsize, vert_step);
 		} else {
 			child_wid->current_y = child_wid->smallest_y;
@@ -1522,6 +1542,16 @@ void NWidgetVertical::AssignSizePosition(SizingType sizing, uint x, uint y, uint
 		child_wid->current_x = ComputeMaxSize(child_wid->smallest_x, given_width - child_wid->padding_left - child_wid->padding_right, hor_step);
 	}
 
+	/* First.5 loop: count how many children are of the biggest step size. */
+	if ((this->flags & NC_BIGFIRST) && biggest_stepsize > 0) {
+		for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
+			uint vert_step = child_wid->GetVerticalStepSize(sizing);
+			if (vert_step == biggest_stepsize) {
+				num_changing_childs++;
+			}
+		}
+	}
+
 	/* Second loop: Allocate the additional vertical space over the resizing children, starting with the biggest resize steps. */
 	while (biggest_stepsize > 0) {
 		uint next_biggest_stepsize = 0;
@@ -1539,6 +1569,16 @@ void NWidgetVertical::AssignSizePosition(SizingType sizing, uint x, uint y, uint
 			next_biggest_stepsize = std::max(next_biggest_stepsize, vert_step);
 		}
 		biggest_stepsize = next_biggest_stepsize;
+
+		if (num_changing_childs == 0 && (flags & NC_BIGFIRST) && biggest_stepsize > 0) {
+			/* Second.5 loop: count how many children are of the updated biggest step size. */
+			for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
+				uint vert_step = child_wid->GetVerticalStepSize(sizing);
+				if (vert_step == biggest_stepsize) {
+					num_changing_childs++;
+				}
+			}
+		}
 	}
 	assert(num_changing_childs == 0);
 
diff --git a/src/widget_type.h b/src/widget_type.h
index a5bd988492..4c812e42f1 100644
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -458,9 +458,11 @@ public:
 /** Nested widget container flags, */
 enum NWidContainerFlags {
 	NCB_EQUALSIZE = 0, ///< Containers should keep all their (resizing) children equally large.
+	NCB_BIGFIRST  = 1, ///< Allocate space to biggest resize first.
 
 	NC_NONE = 0,                       ///< All flags cleared.
 	NC_EQUALSIZE = 1 << NCB_EQUALSIZE, ///< Value of the #NCB_EQUALSIZE flag.
+	NC_BIGFIRST  = 1 << NCB_BIGFIRST,  ///< Value of the #NCB_BIGFIRST flag.
 };
 DECLARE_ENUM_AS_BIT_SET(NWidContainerFlags)