(svn r15760) -Codechange [FS#2704]: support that the resize box is at the left side of the window too (based on work by Alberth)

4 files changed, 48 insertions, 25 deletions

diff --git a/src/table/sprites.h b/src/table/sprites.h
index 5c14d88ba..c9ca6c98d 100644
--- a/src/table/sprites.h
+++ b/src/table/sprites.h
@@ -49,7 +49,7 @@ enum Sprites {
 
 	/* Extra graphic spritenumbers */
 	SPR_OPENTTD_BASE     = 4896,
-	OPENTTD_SPRITE_COUNT = 149,
+	OPENTTD_SPRITE_COUNT = 150,
 
 	/* Halftile-selection sprites */
 	SPR_HALFTILE_SELECTION_FLAT = SPR_OPENTTD_BASE,
@@ -62,7 +62,8 @@ enum Sprites {
 	SPR_BOX_EMPTY          = SPR_OPENTTD_BASE + 41,
 	SPR_BOX_CHECKED        = SPR_OPENTTD_BASE + 42,
 	SPR_WARNING_SIGN       = SPR_OPENTTD_BASE + 43, // warning sign (shown if there are any newgrf errors)
-	SPR_WINDOW_RESIZE      = SPR_OPENTTD_BASE + 44, // resize icon
+	SPR_WINDOW_RESIZE_RIGHT= SPR_OPENTTD_BASE + 44, // resize icon to the right
+	SPR_WINDOW_RESIZE_LEFT = SPR_OPENTTD_BASE + 149, // resize icon to the left
 	/* Arrow icons pointing in all 4 directions */
 	SPR_ARROW_DOWN         = SPR_OPENTTD_BASE + 45,
 	SPR_ARROW_UP           = SPR_OPENTTD_BASE + 46,
diff --git a/src/widget.cpp b/src/widget.cpp
index ce4f4f160..2643eb9e3 100644
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -451,7 +451,11 @@ void Window::DrawWidgets() const
 
 			clicked = !!(this->flags4 & WF_SIZING);
 			DrawFrameRect(r.left, r.top, r.right, r.bottom, wi->colour, (clicked) ? FR_LOWERED : FR_NONE);
-			DrawSprite(SPR_WINDOW_RESIZE, PAL_NONE, r.left + 3 + clicked, r.top + 3 + clicked);
+			if (wi->left < (this->width / 2)) {
+				DrawSprite(SPR_WINDOW_RESIZE_LEFT, PAL_NONE, r.left + 2, r.top + 3 + clicked);
+			} else {
+				DrawSprite(SPR_WINDOW_RESIZE_RIGHT, PAL_NONE, r.left + 3 + clicked, r.top + 3 + clicked);
+			}
 			break;
 
 		case WWT_CLOSEBOX: {
diff --git a/src/window.cpp b/src/window.cpp
index b73c4a6ba..ad8bbc889 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -228,7 +228,7 @@ bool Window::HasWidgetOfType(WidgetType widget_type) const
 }
 
 static void StartWindowDrag(Window *w);
-static void StartWindowSizing(Window *w);
+static void StartWindowSizing(Window *w, bool to_left);
 
 /**
  * Dispatch left mouse-button (possibly double) click in window.
@@ -322,7 +322,9 @@ static void DispatchLeftClickEvent(Window *w, int x, int y, bool double_click)
 		}
 
 		if (w->desc_flags & WDF_RESIZABLE && wi->type == WWT_RESIZEBOX) {
-			StartWindowSizing(w);
+			/* When the resize widget is on the left size of the window
+			 * we assume that that button is used to resize to the left. */
+			StartWindowSizing(w, wi->left < (w->width / 2));
 			w->InvalidateWidget(widget);
 			return;
 		}
@@ -1511,8 +1513,6 @@ static bool HandleWindowDragging()
 			w->SetDirty();
 			return false;
 		} else if (w->flags4 & WF_SIZING) {
-			int x, y;
-
 			/* Stop the sizing if the left mouse button was released */
 			if (!_left_button_down) {
 				w->flags4 &= ~WF_SIZING;
@@ -1520,8 +1520,15 @@ static bool HandleWindowDragging()
 				break;
 			}
 
-			x = _cursor.pos.x - _drag_delta.x;
-			y = _cursor.pos.y - _drag_delta.y;
+			/* Compute difference in pixels between cursor position and reference point in the window.
+			 * If resizing the left edge of the window, moving to the left makes the window bigger not smaller.
+			 */
+			int x, y = _cursor.pos.y - _drag_delta.y;
+			if (w->flags4 & WF_SIZING_LEFT) {
+				x = _drag_delta.x - _cursor.pos.x;
+			} else {
+				x = _cursor.pos.x - _drag_delta.x;
+			}
 
 			/* X and Y has to go by step.. calculate it.
 			 * The cast to int is necessary else x/y are implicitly casted to
@@ -1531,18 +1538,26 @@ static bool HandleWindowDragging()
 			if (w->resize.step_height > 1) y -= y % (int)w->resize.step_height;
 
 			/* Check if we don't go below the minimum set size */
-			if ((int)w->width + x < (int)w->resize.width)
+			if ((int)w->width + x < (int)w->resize.width) {
 				x = w->resize.width - w->width;
-			if ((int)w->height + y < (int)w->resize.height)
+			}
+			if ((int)w->height + y < (int)w->resize.height) {
 				y = w->resize.height - w->height;
+			}
 
 			/* Window already on size */
 			if (x == 0 && y == 0) return false;
 
-			/* Now find the new cursor pos.. this is NOT _cursor, because
-			    we move in steps. */
-			_drag_delta.x += x;
+			/* Now find the new cursor pos.. this is NOT _cursor, because we move in steps. */
 			_drag_delta.y += y;
+			if (w->flags4 & WF_SIZING_LEFT && x != 0) {
+				_drag_delta.x -= x; // x > 0 -> window gets longer -> left-edge moves to left -> subtract x to get new position.
+				w->SetDirty();
+				w->left -= x;  // If dragging left edge, move left window edge in opposite direction by the same amount.
+				/* ResizeWindow() below ensures marking new position as dirty. */
+			} else {
+				_drag_delta.x += x;
+			}
 
 			/* ResizeWindow sets both pre- and after-size to dirty for redrawal */
 			ResizeWindow(w, x, y);
@@ -1579,12 +1594,13 @@ static void StartWindowDrag(Window *w)
 }
 
 /**
- * Start resizing a window
- * @param w Window to start resizing
+ * Start resizing a window.
+ * @param w       Window to start resizing.
+ * @param to_left Whether to drag towards the left or not
  */
-static void StartWindowSizing(Window *w)
+static void StartWindowSizing(Window *w, bool to_left)
 {
-	w->flags4 |= WF_SIZING;
+	w->flags4 |= to_left ? WF_SIZING_LEFT : WF_SIZING_RIGHT;
 	_dragging_window = true;
 
 	_drag_delta.x = _cursor.pos.x;
diff --git a/src/window_gui.h b/src/window_gui.h
index bfcb33cba..f873eb94a 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -587,15 +587,17 @@ enum WindowFlags {
 	WF_SCROLL_UP         = 1 <<  4, ///< Upper scroll button has been pressed, @see ScrollbarClickHandler()
 	WF_SCROLL_DOWN       = 1 <<  5, ///< Lower scroll button has been pressed, @see ScrollbarClickHandler()
 	WF_SCROLL_MIDDLE     = 1 <<  6, ///< Scrollbar scrolling, @see ScrollbarClickHandler()
-	WF_HSCROLL           = 1 <<  7,
-	WF_SIZING            = 1 <<  8, ///< Window is being resized.
-	WF_STICKY            = 1 <<  9, ///< Window is made sticky by user
+	WF_SCROLL2           = 1 <<  7,
+	WF_HSCROLL           = 1 <<  8,
+	WF_SIZING_RIGHT      = 1 <<  9, ///< Window is being resized towards the right.
+	WF_SIZING_LEFT       = 1 << 10, ///< Window is being resized towards the left.
+	WF_SIZING            = WF_SIZING_RIGHT | WF_SIZING_LEFT, ///< Window is being resized.
+	WF_STICKY            = 1 << 11, ///< Window is made sticky by user
 
-	WF_DISABLE_VP_SCROLL = 1 << 10, ///< Window does not do autoscroll, @see HandleAutoscroll()
+	WF_DISABLE_VP_SCROLL = 1 << 12, ///< Window does not do autoscroll, @see HandleAutoscroll()
 
-	WF_WHITE_BORDER_ONE  = 1 << 11,
-	WF_WHITE_BORDER_MASK = 1 << 12 | WF_WHITE_BORDER_ONE,
-	WF_SCROLL2           = 1 << 13,
+	WF_WHITE_BORDER_ONE  = 1 << 13,
+	WF_WHITE_BORDER_MASK = 1 << 14 | WF_WHITE_BORDER_ONE,
 };
 
 Window *BringWindowToFrontById(WindowClass cls, WindowNumber number);