Codechange: Add internal widget alignment property, along with widget part.

6 files changed, 142 insertions, 55 deletions

diff --git a/src/gfx_func.h b/src/gfx_func.h
index e8f7d0345..a4db8a045 100644
--- a/src/gfx_func.h
+++ b/src/gfx_func.h
@@ -91,24 +91,6 @@ Dimension GetSpriteSize(SpriteID sprid, Point *offset = nullptr, ZoomLevel zoom
 void DrawSpriteViewport(SpriteID img, PaletteID pal, int x, int y, const SubSprite *sub = nullptr);
 void DrawSprite(SpriteID img, PaletteID pal, int x, int y, const SubSprite *sub = nullptr, ZoomLevel zoom = ZOOM_LVL_GUI);
 
-/** How to align the to-be drawn text. */
-enum StringAlignment {
-	SA_LEFT        = 0 << 0, ///< Left align the text.
-	SA_HOR_CENTER  = 1 << 0, ///< Horizontally center the text.
-	SA_RIGHT       = 2 << 0, ///< Right align the text (must be a single bit).
-	SA_HOR_MASK    = 3 << 0, ///< Mask for horizontal alignment.
-
-	SA_TOP         = 0 << 2, ///< Top align the text.
-	SA_VERT_CENTER = 1 << 2, ///< Vertically center the text.
-	SA_BOTTOM      = 2 << 2, ///< Bottom align the text.
-	SA_VERT_MASK   = 3 << 2, ///< Mask for vertical alignment.
-
-	SA_CENTER      = SA_HOR_CENTER | SA_VERT_CENTER, ///< Center both horizontally and vertically.
-
-	SA_FORCE       = 1 << 4, ///< Force the alignment, i.e. don't swap for RTL languages.
-};
-DECLARE_ENUM_AS_BIT_SET(StringAlignment)
-
 int DrawString(int left, int right, int top, const char *str, TextColour colour = TC_FROMSTRING, StringAlignment align = SA_LEFT, bool underline = false, FontSize fontsize = FS_NORMAL);
 int DrawString(int left, int right, int top, StringID str, TextColour colour = TC_FROMSTRING, StringAlignment align = SA_LEFT, bool underline = false, FontSize fontsize = FS_NORMAL);
 int DrawStringMultiLine(int left, int right, int top, int bottom, const char *str, TextColour colour = TC_FROMSTRING, StringAlignment align = (SA_TOP | SA_LEFT), bool underline = false, FontSize fontsize = FS_NORMAL);
diff --git a/src/gfx_type.h b/src/gfx_type.h
index 3b9f04d9e..a6bf3cf6d 100644
--- a/src/gfx_type.h
+++ b/src/gfx_type.h
@@ -323,4 +323,22 @@ enum Support8bpp {
 	S8BPP_HARDWARE, ///< Full 8bpp support by OS and hardware.
 };
 
+	/** How to align the to-be drawn text. */
+enum StringAlignment {
+	SA_LEFT        = 0 << 0, ///< Left align the text.
+	SA_HOR_CENTER  = 1 << 0, ///< Horizontally center the text.
+	SA_RIGHT       = 2 << 0, ///< Right align the text (must be a single bit).
+	SA_HOR_MASK    = 3 << 0, ///< Mask for horizontal alignment.
+
+	SA_TOP         = 0 << 2, ///< Top align the text.
+	SA_VERT_CENTER = 1 << 2, ///< Vertically center the text.
+	SA_BOTTOM      = 2 << 2, ///< Bottom align the text.
+	SA_VERT_MASK   = 3 << 2, ///< Mask for vertical alignment.
+
+	SA_CENTER      = SA_HOR_CENTER | SA_VERT_CENTER, ///< Center both horizontally and vertically.
+
+	SA_FORCE       = 1 << 4, ///< Force the alignment, i.e. don't swap for RTL languages.
+};
+DECLARE_ENUM_AS_BIT_SET(StringAlignment)
+
 #endif /* GFX_TYPE_H */
diff --git a/src/news_gui.cpp b/src/news_gui.cpp
index fdcb56a37..fa601eb56 100644
--- a/src/news_gui.cpp
+++ b/src/news_gui.cpp
@@ -422,7 +422,7 @@ struct NewsWindow : Window {
 	{
 		switch (widget) {
 			case WID_N_CAPTION:
-				DrawCaption(r, COLOUR_LIGHT_BLUE, this->owner, STR_NEWS_MESSAGE_CAPTION);
+				DrawCaption(r, COLOUR_LIGHT_BLUE, this->owner, STR_NEWS_MESSAGE_CAPTION, SA_HOR_CENTER);
 				break;
 
 			case WID_N_PANEL:
diff --git a/src/widget.cpp b/src/widget.cpp
index 123e8a2f9..feaf036b2 100644
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -25,6 +25,33 @@
 #include "safeguards.h"
 
 /**
+ * Calculate x and y coordinates for an aligned object within a window.
+ * @param r     Rectangle of the widget to be drawn in.
+ * @param d     Dimension of the object to be drawn.
+ * @param align Alignment of the object.
+ * @return A point containing the position at which to draw.
+ */
+static inline Point GetAlignedPosition(const Rect &r, const Dimension &d, StringAlignment align)
+{
+	Point p;
+	/* In case we have a RTL language we swap the alignment. */
+	if (!(align & SA_FORCE) && _current_text_dir == TD_RTL && (align & SA_HOR_MASK) != SA_HOR_CENTER) align ^= SA_RIGHT;
+	switch (align & SA_HOR_MASK) {
+		case SA_LEFT:       p.x = r.left; break;
+		case SA_HOR_CENTER: p.x = CenterBounds(r.left, r.right, d.width); break;
+		case SA_RIGHT:      p.x = r.right - d.width; break;
+		default: NOT_REACHED();
+	}
+	switch (align & SA_VERT_MASK) {
+		case SA_TOP:         p.y = r.top; break;
+		case SA_VERT_CENTER: p.y = CenterBounds(r.top, r.bottom, d.height); break;
+		case SA_BOTTOM:      p.y = r.bottom - d.height; break;
+		default: NOT_REACHED();
+	}
+	return p;
+}
+
+/**
  * Compute the vertical position of the draggable part of scrollbar
  * @param sb     Scrollbar list data
  * @param top    Top position of the scrollbar (top position of the up-button)
@@ -212,15 +239,17 @@ void DrawFrameRect(int left, int top, int right, int bottom, Colours colour, Fra
  * @param colour  Colour of the button.
  * @param clicked Button is lowered.
  * @param img     Sprite to draw.
+ * @param align   Alignment of the sprite.
  */
-static inline void DrawImageButtons(const Rect &r, WidgetType type, Colours colour, bool clicked, SpriteID img)
+static inline void DrawImageButtons(const Rect &r, WidgetType type, Colours colour, bool clicked, SpriteID img, StringAlignment align)
 {
 	assert(img != 0);
 	DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, (clicked) ? FR_LOWERED : FR_NONE);
 
 	if ((type & WWT_MASK) == WWT_IMGBTN_2 && clicked) img++; // Show different image when clicked for #WWT_IMGBTN_2.
 	Dimension d = GetSpriteSize(img);
-	DrawSprite(img, PAL_NONE, CenterBounds(r.left, r.right, d.width) + clicked, CenterBounds(r.top, r.bottom, d.height) + clicked);
+	Point p = GetAlignedPosition(r, d, align);
+	DrawSprite(img, PAL_NONE, p.x + clicked, p.y + clicked);
 }
 
 /**
@@ -229,14 +258,15 @@ static inline void DrawImageButtons(const Rect &r, WidgetType type, Colours colo
  * @param type    Widget type (#WWT_TEXTBTN, #WWT_TEXTBTN_2, or #WWT_LABEL).
  * @param clicked Label is rendered lowered.
  * @param str     Text to draw.
+ * @param align   Alignment of the text.
  */
-static inline void DrawLabel(const Rect &r, WidgetType type, bool clicked, StringID str)
+static inline void DrawLabel(const Rect &r, WidgetType type, bool clicked, StringID str, StringAlignment align)
 {
 	if (str == STR_NULL) return;
 	if ((type & WWT_MASK) == WWT_TEXTBTN_2 && clicked) str++;
 	Dimension d = GetStringBoundingBox(str);
-	int offset = std::max(0, ((int)(r.bottom - r.top + 1) - (int)d.height) / 2); // Offset for rendering the text vertically centered
-	DrawString(r.left + clicked, r.right + clicked, r.top + offset + clicked, str, TC_FROMSTRING, SA_HOR_CENTER);
+	Point p = GetAlignedPosition(r, d, align);
+	DrawString(r.left + clicked, r.right + clicked, p.y + clicked, str, TC_FROMSTRING, align);
 }
 
 /**
@@ -244,12 +274,13 @@ static inline void DrawLabel(const Rect &r, WidgetType type, bool clicked, Strin
  * @param r      Rectangle of the background.
  * @param colour Colour of the text.
  * @param str    Text to draw.
+ * @param align  Alignment of the text.
  */
-static inline void DrawText(const Rect &r, TextColour colour, StringID str)
+static inline void DrawText(const Rect &r, TextColour colour, StringID str, StringAlignment align)
 {
 	Dimension d = GetStringBoundingBox(str);
-	int offset = std::max(0, ((int)(r.bottom - r.top + 1) - (int)d.height) / 2); // Offset for rendering the text vertically centered
-	if (str != STR_NULL) DrawString(r.left, r.right, r.top + offset, str, colour);
+	Point p = GetAlignedPosition(r, d, align);
+	if (str != STR_NULL) DrawString(r.left, r.right, p.y, str, colour, align);
 }
 
 /**
@@ -257,11 +288,12 @@ static inline void DrawText(const Rect &r, TextColour colour, StringID str)
  * @param r      Rectangle of the background.
  * @param colour Colour of the inset.
  * @param str    Text to draw.
+ * @param align  Alignment of the text.
  */
-static inline void DrawInset(const Rect &r, Colours colour, StringID str)
+static inline void DrawInset(const Rect &r, Colours colour, StringID str, StringAlignment align)
 {
 	DrawFrameRect(r.left, r.top, r.right, r.bottom, colour, FR_LOWERED | FR_DARKENED);
-	if (str != STR_NULL) DrawString(r.left + WD_INSET_LEFT, r.right - WD_INSET_RIGHT, r.top + WD_INSET_TOP, str);
+	if (str != STR_NULL) DrawString(r.left + WD_INSET_LEFT, r.right - WD_INSET_RIGHT, r.top + WD_INSET_TOP, str, TC_FROMSTRING, align);
 }
 
 /**
@@ -405,12 +437,13 @@ static inline void DrawHorizontalScrollbar(const Rect &r, Colours colour, bool l
  * @param r      Rectangle of the frame.
  * @param colour Colour of the frame.
  * @param str    Text of the frame.
+ * @param align  Alignment of the text in the frame.
  */
-static inline void DrawFrame(const Rect &r, Colours colour, StringID str)
+static inline void DrawFrame(const Rect &r, Colours colour, StringID str, StringAlignment align)
 {
 	int x2 = r.left; // by default the left side is the left side of the widget
 
-	if (str != STR_NULL) x2 = DrawString(r.left + WD_FRAMETEXT_LEFT, r.right - WD_FRAMETEXT_RIGHT, r.top, str);
+	if (str != STR_NULL) x2 = DrawString(r.left + WD_FRAMETEXT_LEFT, r.right - WD_FRAMETEXT_RIGHT, r.top, str, TC_FROMSTRING, align);
 
 	int c1 = _colour_gradient[colour][3];
 	int c2 = _colour_gradient[colour][7];
@@ -458,7 +491,7 @@ static inline void DrawFrame(const Rect &r, Colours colour, StringID str)
  */
 static inline void DrawShadeBox(const Rect &r, Colours colour, bool clicked)
 {
-	DrawImageButtons(r, WWT_SHADEBOX, colour, clicked, clicked ? SPR_WINDOW_SHADE: SPR_WINDOW_UNSHADE);
+	DrawImageButtons(r, WWT_SHADEBOX, colour, clicked, clicked ? SPR_WINDOW_SHADE: SPR_WINDOW_UNSHADE, SA_CENTER);
 }
 
 /**
@@ -469,7 +502,7 @@ static inline void DrawShadeBox(const Rect &r, Colours colour, bool clicked)
  */
 static inline void DrawStickyBox(const Rect &r, Colours colour, bool clicked)
 {
-	DrawImageButtons(r, WWT_STICKYBOX, colour, clicked, clicked ? SPR_PIN_UP : SPR_PIN_DOWN);
+	DrawImageButtons(r, WWT_STICKYBOX, colour, clicked, clicked ? SPR_PIN_UP : SPR_PIN_DOWN, SA_CENTER);
 }
 
 /**
@@ -480,7 +513,7 @@ static inline void DrawStickyBox(const Rect &r, Colours colour, bool clicked)
  */
 static inline void DrawDefSizeBox(const Rect &r, Colours colour, bool clicked)
 {
-	DrawImageButtons(r, WWT_DEFSIZEBOX, colour, clicked, SPR_WINDOW_DEFSIZE);
+	DrawImageButtons(r, WWT_DEFSIZEBOX, colour, clicked, SPR_WINDOW_DEFSIZE, SA_CENTER);
 }
 
 /**
@@ -491,7 +524,7 @@ static inline void DrawDefSizeBox(const Rect &r, Colours colour, bool clicked)
  */
 static inline void DrawDebugBox(const Rect &r, Colours colour, bool clicked)
 {
-	DrawImageButtons(r, WWT_DEBUGBOX, colour, clicked, SPR_WINDOW_DEBUG);
+	DrawImageButtons(r, WWT_DEBUGBOX, colour, clicked, SPR_WINDOW_DEBUG, SA_CENTER);
 }
 
 /**
@@ -534,8 +567,9 @@ static inline void DrawCloseBox(const Rect &r, Colours colour)
  * @param colour Colour of the window.
  * @param owner  'Owner' of the window.
  * @param str    Text to draw in the bar.
+ * @param align  Alignment of the text.
  */
-void DrawCaption(const Rect &r, Colours colour, Owner owner, StringID str)
+void DrawCaption(const Rect &r, Colours colour, Owner owner, StringID str, StringAlignment align)
 {
 	bool company_owned = owner < MAX_COMPANIES;
 
@@ -548,8 +582,8 @@ void DrawCaption(const Rect &r, Colours colour, Owner owner, StringID str)
 
 	if (str != STR_NULL) {
 		Dimension d = GetStringBoundingBox(str);
-		int offset = std::max(0, ((int)(r.bottom - r.top + 1) - (int)d.height) / 2); // Offset for rendering the text vertically centered
-		DrawString(r.left + WD_CAPTIONTEXT_LEFT, r.right - WD_CAPTIONTEXT_RIGHT, r.top + offset, str, TC_FROMSTRING, SA_HOR_CENTER);
+		Point p = GetAlignedPosition(r, d, align);
+		DrawString(r.left + WD_CAPTIONTEXT_LEFT, r.right - WD_CAPTIONTEXT_RIGHT, p.y, str, TC_FROMSTRING, align);
 	}
 }
 
@@ -560,10 +594,11 @@ void DrawCaption(const Rect &r, Colours colour, Owner owner, StringID str)
  * @param clicked_button   The button-part is lowered.
  * @param clicked_dropdown The drop-down part is lowered.
  * @param str              Text of the button.
+ * @param align            Alignment of the text within the dropdown.
  *
  * @note Magic constants are also used in #NWidgetLeaf::ButtonHit.
  */
-static inline void DrawButtonDropdown(const Rect &r, Colours colour, bool clicked_button, bool clicked_dropdown, StringID str)
+static inline void DrawButtonDropdown(const Rect &r, Colours colour, bool clicked_button, bool clicked_dropdown, StringID str, StringAlignment align)
 {
 	int text_offset = std::max(0, ((int)(r.bottom - r.top + 1) - FONT_HEIGHT_NORMAL) / 2); // Offset for rendering the text vertically centered
 
@@ -575,12 +610,12 @@ static inline void DrawButtonDropdown(const Rect &r, Colours colour, bool clicke
 		DrawFrameRect(r.left, r.top, r.right - dd_width, r.bottom, colour, clicked_button ? FR_LOWERED : FR_NONE);
 		DrawFrameRect(r.right + 1 - dd_width, r.top, r.right, r.bottom, colour, clicked_dropdown ? FR_LOWERED : FR_NONE);
 		DrawSprite(SPR_ARROW_DOWN, PAL_NONE, r.right - (dd_width - 2) + clicked_dropdown, r.top + image_offset + clicked_dropdown);
-		if (str != STR_NULL) DrawString(r.left + WD_DROPDOWNTEXT_LEFT + clicked_button, r.right - dd_width - WD_DROPDOWNTEXT_RIGHT + clicked_button, r.top + text_offset + clicked_button, str, TC_BLACK);
+		if (str != STR_NULL) DrawString(r.left + WD_DROPDOWNTEXT_LEFT + clicked_button, r.right - dd_width - WD_DROPDOWNTEXT_RIGHT + clicked_button, r.top + text_offset + clicked_button, str, TC_BLACK, align);
 	} else {
 		DrawFrameRect(r.left + dd_width, r.top, r.right, r.bottom, colour, clicked_button ? FR_LOWERED : FR_NONE);
 		DrawFrameRect(r.left, r.top, r.left + dd_width - 1, r.bottom, colour, clicked_dropdown ? FR_LOWERED : FR_NONE);
 		DrawSprite(SPR_ARROW_DOWN, PAL_NONE, r.left + 1 + clicked_dropdown, r.top + image_offset + clicked_dropdown);
-		if (str != STR_NULL) DrawString(r.left + dd_width + WD_DROPDOWNTEXT_LEFT + clicked_button, r.right - WD_DROPDOWNTEXT_RIGHT + clicked_button, r.top + text_offset + clicked_button, str, TC_BLACK);
+		if (str != STR_NULL) DrawString(r.left + dd_width + WD_DROPDOWNTEXT_LEFT + clicked_button, r.right - WD_DROPDOWNTEXT_RIGHT + clicked_button, r.top + text_offset + clicked_button, str, TC_BLACK, align);
 	}
 }
 
@@ -590,10 +625,11 @@ static inline void DrawButtonDropdown(const Rect &r, Colours colour, bool clicke
  * @param colour  Background colour of the widget.
  * @param clicked The widget is lowered.
  * @param str     Text of the button.
+ * @param align   Alignment of the text.
  */
-static inline void DrawDropdown(const Rect &r, Colours colour, bool clicked, StringID str)
+static inline void DrawDropdown(const Rect &r, Colours colour, bool clicked, StringID str, StringAlignment align)
 {
-	DrawButtonDropdown(r, colour, false, clicked, str);
+	DrawButtonDropdown(r, colour, false, clicked, str, align);
 }
 
 /**
@@ -872,6 +908,7 @@ NWidgetCore::NWidgetCore(WidgetType tp, Colours colour, uint fill_x, uint fill_y
 	this->widget_data = widget_data;
 	this->tool_tip = tool_tip;
 	this->scrollbar_index = -1;
+	this->align = SA_CENTER;
 }
 
 /**
@@ -904,6 +941,15 @@ void NWidgetCore::SetToolTip(StringID tool_tip)
 	this->tool_tip = tool_tip;
 }
 
+/**
+ * Set the text/image alignment of the nested widget.
+ * @param align Alignment to use.
+ */
+void NWidgetCore::SetAlignment(StringAlignment align)
+{
+	this->align = align;
+}
+
 void NWidgetCore::FillNestedArray(NWidgetBase **array, uint length)
 {
 	if (this->index >= 0 && (uint)(this->index) < length) array[this->index] = this;
@@ -1725,6 +1771,7 @@ NWidgetBackground::NWidgetBackground(WidgetType tp, Colours colour, int index, N
 	assert(tp == WWT_PANEL || tp == WWT_INSET || tp == WWT_FRAME);
 	if (index >= 0) this->SetIndex(index);
 	this->child = child;
+	this->SetAlignment(SA_TOP | SA_LEFT);
 }
 
 NWidgetBackground::~NWidgetBackground()
@@ -1858,12 +1905,12 @@ void NWidgetBackground::Draw(const Window *w)
 
 		case WWT_FRAME:
 			if (this->index >= 0) w->SetStringParameters(this->index);
-			DrawFrame(r, this->colour, this->widget_data);
+			DrawFrame(r, this->colour, this->widget_data, this->align);
 			break;
 
 		case WWT_INSET:
 			if (this->index >= 0) w->SetStringParameters(this->index);
-			DrawInset(r, this->colour, this->widget_data);
+			DrawInset(r, this->colour, this->widget_data, this->align);
 			break;
 
 		default:
@@ -2192,6 +2239,11 @@ NWidgetLeaf::NWidgetLeaf(WidgetType tp, Colours colour, int index, uint32 data,
 		case WWT_EMPTY:
 			break;
 
+		case WWT_TEXT:
+			this->SetFill(0, 0);
+			this->SetAlignment(SA_LEFT | SA_VERT_CENTER);
+			break;
+
 		case WWT_PUSHBTN:
 		case WWT_IMGBTN:
 		case WWT_PUSHIMGBTN:
@@ -2200,7 +2252,6 @@ NWidgetLeaf::NWidgetLeaf(WidgetType tp, Colours colour, int index, uint32 data,
 		case WWT_PUSHTXTBTN:
 		case WWT_TEXTBTN_2:
 		case WWT_LABEL:
-		case WWT_TEXT:
 		case WWT_MATRIX:
 		case NWID_BUTTON_DROPDOWN:
 		case NWID_PUSHBUTTON_DROPDOWN:
@@ -2259,6 +2310,7 @@ NWidgetLeaf::NWidgetLeaf(WidgetType tp, Colours colour, int index, uint32 data,
 		case WWT_DROPDOWN:
 			this->SetFill(0, 0);
 			this->min_y = WD_DROPDOWN_HEIGHT;
+			this->SetAlignment(SA_TOP | SA_LEFT);
 			break;
 
 		default:
@@ -2493,7 +2545,7 @@ void NWidgetLeaf::Draw(const Window *w)
 		case WWT_IMGBTN:
 		case WWT_PUSHIMGBTN:
 		case WWT_IMGBTN_2:
-			DrawImageButtons(r, this->type, this->colour, clicked, this->widget_data);
+			DrawImageButtons(r, this->type, this->colour, clicked, this->widget_data, this->align);
 			break;
 
 		case WWT_TEXTBTN:
@@ -2501,7 +2553,7 @@ void NWidgetLeaf::Draw(const Window *w)
 		case WWT_TEXTBTN_2:
 			if (this->index >= 0) w->SetStringParameters(this->index);
 			DrawFrameRect(r.left, r.top, r.right, r.bottom, this->colour, (clicked) ? FR_LOWERED : FR_NONE);
-			DrawLabel(r, this->type, clicked, this->widget_data);
+			DrawLabel(r, this->type, clicked, this->widget_data, this->align);
 			break;
 
 		case WWT_ARROWBTN:
@@ -2514,18 +2566,18 @@ void NWidgetLeaf::Draw(const Window *w)
 				case AWV_RIGHT:    sprite = SPR_ARROW_RIGHT; break;
 				default: NOT_REACHED();
 			}
-			DrawImageButtons(r, WWT_PUSHIMGBTN, this->colour, clicked, sprite);
+			DrawImageButtons(r, WWT_PUSHIMGBTN, this->colour, clicked, sprite, this->align);
 			break;
 		}
 
 		case WWT_LABEL:
 			if (this->index >= 0) w->SetStringParameters(this->index);
-			DrawLabel(r, this->type, clicked, this->widget_data);
+			DrawLabel(r, this->type, clicked, this->widget_data, this->align);
 			break;
 
 		case WWT_TEXT:
 			if (this->index >= 0) w->SetStringParameters(this->index);
-			DrawText(r, (TextColour)this->colour, this->widget_data);
+			DrawText(r, (TextColour)this->colour, this->widget_data, this->align);
 			break;
 
 		case WWT_MATRIX:
@@ -2540,7 +2592,7 @@ void NWidgetLeaf::Draw(const Window *w)
 
 		case WWT_CAPTION:
 			if (this->index >= 0) w->SetStringParameters(this->index);
-			DrawCaption(r, this->colour, w->owner, this->widget_data);
+			DrawCaption(r, this->colour, w->owner, this->widget_data, this->align);
 			break;
 
 		case WWT_SHADEBOX:
@@ -2573,13 +2625,13 @@ void NWidgetLeaf::Draw(const Window *w)
 
 		case WWT_DROPDOWN:
 			if (this->index >= 0) w->SetStringParameters(this->index);
-			DrawDropdown(r, this->colour, clicked, this->widget_data);
+			DrawDropdown(r, this->colour, clicked, this->widget_data, this->align);
 			break;
 
 		case NWID_BUTTON_DROPDOWN:
 		case NWID_PUSHBUTTON_DROPDOWN:
 			if (this->index >= 0) w->SetStringParameters(this->index);
-			DrawButtonDropdown(r, this->colour, clicked, (this->disp_flags & ND_DROPDOWN_ACTIVE) != 0, this->widget_data);
+			DrawButtonDropdown(r, this->colour, clicked, (this->disp_flags & ND_DROPDOWN_ACTIVE) != 0, this->widget_data, this->align);
 			break;
 
 		default:
@@ -2718,6 +2770,14 @@ static int MakeNWidget(const NWidgetPart *parts, int count, NWidgetBase **dest,
 				break;
 			}
 
+			case WPT_ALIGNMENT: {
+				NWidgetCore *nwc = dynamic_cast<NWidgetCore *>(*dest);
+				if (nwc != nullptr) {
+					nwc->SetAlignment(parts->u.align.align);
+				}
+				break;
+			}
+
 			case WPT_FILL: {
 				NWidgetResizeBase *nwrb = dynamic_cast<NWidgetResizeBase *>(*dest);
 				if (nwrb != nullptr) nwrb->SetFill(parts->u.xy.x, parts->u.xy.y);
diff --git a/src/widget_type.h b/src/widget_type.h
index a5b323b87..97f64ba1b 100644
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -89,6 +89,7 @@ enum WidgetType {
 	WPT_DATATIP,      ///< Widget part for specifying data and tooltip.
 	WPT_PADDING,      ///< Widget part for specifying a padding.
 	WPT_PIPSPACE,     ///< Widget part for specifying pre/inter/post space for containers.
+	WPT_ALIGNMENT,    ///< Widget part for specifying text/image alignment.
 	WPT_ENDCONTAINER, ///< Widget part to denote end of a container.
 	WPT_FUNCTION,     ///< Widget part for calling a user function.
 	WPT_SCROLLBAR,    ///< Widget part for attaching a scrollbar.
@@ -296,6 +297,7 @@ public:
 	void SetIndex(int index);
 	void SetDataTip(uint32 widget_data, StringID tool_tip);
 	void SetToolTip(StringID tool_tip);
+	void SetAlignment(StringAlignment align);
 
 	inline void SetLowered(bool lowered);
 	inline bool IsLowered() const;
@@ -315,6 +317,7 @@ public:
 	StringID tool_tip;         ///< Tooltip of the widget. @see Widget::tootips
 	int scrollbar_index;       ///< Index of an attached scrollbar.
 	TextColour highlight_colour; ///< Colour of highlight.
+	StringAlignment align;     ///< Alignment of text/image within widget.
 };
 
 /**
@@ -906,6 +909,14 @@ struct NWidgetPartTextLines {
 };
 
 /**
+ * Widget part for setting text/image alignment within a widget.
+ * @ingroup NestedWidgetParts
+ */
+struct NWidgetPartAlignment {
+	StringAlignment align; ///< Alignment of text/image.
+};
+
+/**
  * Pointer to function returning a nested widget.
  * @param biggest_index Pointer to storage for collecting the biggest index used in the nested widget.
  * @return Nested widget (tree).
@@ -926,6 +937,7 @@ struct NWidgetPart {
 		NWidgetPartPaddings padding;     ///< Part with paddings.
 		NWidgetPartPIP pip;              ///< Part with pre/inter/post spaces.
 		NWidgetPartTextLines text_lines; ///< Part with text line data.
+		NWidgetPartAlignment align;      ///< Part with internal alignment.
 		NWidgetFunctionType *func_ptr;   ///< Part with a function call.
 		NWidContainerFlags cont_flags;   ///< Part with container flags.
 	} u;
@@ -985,6 +997,21 @@ static inline NWidgetPart SetMinimalTextLines(uint8 lines, uint8 spacing, FontSi
 }
 
 /**
+ * Widget part function for setting the alignment of text/images.
+ * @param align  Alignment of text/image within widget.
+ * @ingroup NestedWidgetParts
+ */
+static inline NWidgetPart SetAlignment(StringAlignment align)
+{
+	NWidgetPart part;
+
+	part.type = WPT_ALIGNMENT;
+	part.u.align.align = align;
+
+	return part;
+}
+
+/**
  * Widget part function for setting filling.
  * @param fill_x Horizontal filling step from minimal size.
  * @param fill_y Vertical filling step from minimal size.
diff --git a/src/window_gui.h b/src/window_gui.h
index aca7f4486..1799001c9 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -140,7 +140,7 @@ enum WidgetDrawDistances {
 
 /* widget.cpp */
 void DrawFrameRect(int left, int top, int right, int bottom, Colours colour, FrameFlags flags);
-void DrawCaption(const Rect &r, Colours colour, Owner owner, StringID str);
+void DrawCaption(const Rect &r, Colours colour, Owner owner, StringID str, StringAlignment align);
 
 /* window.cpp */
 extern Window *_z_front_window;