--- a/src/functions.h	Fri Oct 05 21:31:59 2007 +0000
+++ b/src/functions.h	Fri Oct 05 21:49:15 2007 +0000
@@ -132,7 +132,6 @@
 
 bool ScrollMainWindowToTile(TileIndex tile, bool instant = false);
 bool ScrollMainWindowTo(int x, int y, bool instant = false);
-void DrawSprite(SpriteID img, SpriteID pal, int x, int y);
 bool EnsureNoVehicle(TileIndex tile);
 bool EnsureNoVehicleOnGround(TileIndex tile);
 

--- a/src/gfx.cpp	Fri Oct 05 21:31:59 2007 +0000
+++ b/src/gfx.cpp	Fri Oct 05 21:49:15 2007 +0000
@@ -43,7 +43,7 @@
 Colour _cur_palette[256];
 byte _stringwidth_table[FS_END][224];
 
-static void GfxMainBlitter(const Sprite *sprite, int x, int y, BlitterMode mode);
+static void GfxMainBlitter(const Sprite *sprite, int x, int y, BlitterMode mode, const SubSprite *sub = NULL);
 
 FontSize _cur_fontsize;
 static FontSize _last_fontsize;
@@ -652,24 +652,33 @@
 	return DoDrawString(buffer, x, y, color);
 }
 
-void DrawSprite(SpriteID img, SpriteID pal, int x, int y)
+void DrawSprite(SpriteID img, SpriteID pal, int x, int y, const SubSprite *sub)
 {
 	if (HASBIT(img, PALETTE_MODIFIER_TRANSPARENT)) {
 		_color_remap_ptr = GetNonSprite(GB(pal, 0, PALETTE_WIDTH)) + 1;
-		GfxMainBlitter(GetSprite(GB(img, 0, SPRITE_WIDTH)), x, y, BM_TRANSPARENT);
+		GfxMainBlitter(GetSprite(GB(img, 0, SPRITE_WIDTH)), x, y, BM_TRANSPARENT, sub);
 	} else if (pal != PAL_NONE) {
 		_color_remap_ptr = GetNonSprite(GB(pal, 0, PALETTE_WIDTH)) + 1;
-		GfxMainBlitter(GetSprite(GB(img, 0, SPRITE_WIDTH)), x, y, BM_COLOUR_REMAP);
+		GfxMainBlitter(GetSprite(GB(img, 0, SPRITE_WIDTH)), x, y, BM_COLOUR_REMAP, sub);
 	} else {
-		GfxMainBlitter(GetSprite(GB(img, 0, SPRITE_WIDTH)), x, y, BM_NORMAL);
+		GfxMainBlitter(GetSprite(GB(img, 0, SPRITE_WIDTH)), x, y, BM_NORMAL, sub);
 	}
 }
 
-static inline void GfxMainBlitter(const Sprite *sprite, int x, int y, BlitterMode mode)
+static inline void GfxMainBlitter(const Sprite *sprite, int x, int y, BlitterMode mode, const SubSprite *sub)
 {
 	const DrawPixelInfo *dpi = _cur_dpi;
 	Blitter::BlitterParams bp;
 
+	/* Amount of pixels to clip from the source sprite */
+	int clip_left   = (sub != NULL ? max(0,                   -sprite->x_offs + sub->left       ) : 0);
+	int clip_top    = (sub != NULL ? max(0,                   -sprite->y_offs + sub->top        ) : 0);
+	int clip_right  = (sub != NULL ? max(0, sprite->width  - (-sprite->x_offs + sub->right  + 1)) : 0);
+	int clip_bottom = (sub != NULL ? max(0, sprite->height - (-sprite->y_offs + sub->bottom + 1)) : 0);
+
+	if (clip_left + clip_right >= sprite->width) return;
+	if (clip_top + clip_bottom >= sprite->height) return;
+
 	/* Move to the correct offset */
 	x += sprite->x_offs;
 	y += sprite->y_offs;
@@ -678,12 +687,16 @@
 	bp.sprite = sprite->data;
 	bp.sprite_width = sprite->width;
 	bp.sprite_height = sprite->height;
-	bp.width = UnScaleByZoom(sprite->width, dpi->zoom);
-	bp.height = UnScaleByZoom(sprite->height, dpi->zoom);
+	bp.width = UnScaleByZoom(sprite->width - clip_left - clip_right, dpi->zoom);
+	bp.height = UnScaleByZoom(sprite->height - clip_top - clip_bottom, dpi->zoom);
 	bp.top = 0;
 	bp.left = 0;
-	bp.skip_left = 0;
-	bp.skip_top = 0;
+	bp.skip_left = UnScaleByZoom(clip_left, dpi->zoom);
+	bp.skip_top = UnScaleByZoom(clip_top, dpi->zoom);
+
+	x += ScaleByZoom(bp.skip_left, dpi->zoom);
+	y += ScaleByZoom(bp.skip_top, dpi->zoom);
+
 	bp.dst = dpi->dst_ptr;
 	bp.pitch = dpi->pitch;
 	bp.remap = _color_remap_ptr;

--- a/src/gfx.h	Fri Oct 05 21:31:59 2007 +0000
+++ b/src/gfx.h	Fri Oct 05 21:49:15 2007 +0000
@@ -242,6 +242,16 @@
 void RedrawScreenRect(int left, int top, int right, int bottom);
 void GfxScroll(int left, int top, int width, int height, int xo, int yo);
 
+/**
+ * Used to only draw a part of the sprite.
+ * Draw the subsprite in the rect (sprite_x_offset + left, sprite_y_offset + top) to (sprite_x_offset + right, sprite_y_offset + bottom).
+ * Both corners are included in the drawing area.
+ */
+struct SubSprite {
+	int left, top, right, bottom;
+};
+
+void DrawSprite(SpriteID img, SpriteID pal, int x, int y, const SubSprite *sub = NULL);
 
 /* XXX doesn't really belong here, but the only
  * consumers always use it in conjunction with DoDrawString() */

--- a/src/viewport.cpp	Fri Oct 05 21:31:59 2007 +0000
+++ b/src/viewport.cpp	Fri Oct 05 21:49:15 2007 +0000
@@ -66,6 +66,7 @@
 struct TileSpriteToDraw {
 	SpriteID image;
 	SpriteID pal;
+	const SubSprite *sub;           ///< only draw a rectangular part of the sprite
 	TileSpriteToDraw *next;
 	int32 x;
 	int32 y;
@@ -75,6 +76,7 @@
 struct ChildScreenSpriteToDraw {
 	SpriteID image;
 	SpriteID pal;
+	const SubSprite *sub;           ///< only draw a rectangular part of the sprite
 	int32 x;
 	int32 y;
 	ChildScreenSpriteToDraw *next;
@@ -83,6 +85,7 @@
 struct ParentSpriteToDraw {
 	SpriteID image;                 ///< sprite to draw
 	SpriteID pal;                   ///< palette to use
+	const SubSprite *sub;           ///< only draw a rectangular part of the sprite
 
 	int32 x;                        ///< screen X coordinate of sprite
 	int32 y;                        ///< screen Y coordinate of sprite
@@ -428,7 +431,18 @@
 	InvalidateWidget(w, widget_zoom_out);
 }
 
-void DrawGroundSpriteAt(SpriteID image, SpriteID pal, int32 x, int32 y, byte z)
+/**
+ * Draws a ground sprite at a specific world-coordinate.
+ *
+ * @param image the image to draw.
+ * @param pal the provided palette.
+ * @param x position x of the sprite.
+ * @param y position y of the sprite.
+ * @param z position z of the sprite.
+ * @param sub Only draw a part of the sprite.
+ *
+ */
+void DrawGroundSpriteAt(SpriteID image, SpriteID pal, int32 x, int32 y, byte z, const SubSprite *sub)
 {
 	ViewportDrawer *vd = _cur_vd;
 	TileSpriteToDraw *ts;
@@ -445,6 +459,7 @@
 
 	ts->image = image;
 	ts->pal = pal;
+	ts->sub = sub;
 	ts->next = NULL;
 	ts->x = x;
 	ts->y = y;
@@ -453,14 +468,22 @@
 	vd->last_tile = &ts->next;
 }
 
-void DrawGroundSprite(SpriteID image, SpriteID pal)
+/**
+ * Draws a ground sprite for the current tile.
+ * If the current tile is drawn on top of a foundation the sprite is added as child sprite to the "foundation"-ParentSprite.
+ *
+ * @param image the image to draw.
+ * @param pal the provided palette.
+ * @param sub Only draw a part of the sprite.
+ */
+void DrawGroundSprite(SpriteID image, SpriteID pal, const SubSprite *sub)
 {
 	if (_offset_ground_sprites) {
 		/* offset ground sprite because of foundation? */
-		AddChildSpriteScreen(image, pal, _cur_vd->offs_x, _cur_vd->offs_y);
+		AddChildSpriteScreen(image, pal, _cur_vd->offs_x, _cur_vd->offs_y, false, sub);
 	} else {
 		_added_tile_sprite = true;
-		DrawGroundSpriteAt(image, pal, _cur_ti->x, _cur_ti->y, _cur_ti->z);
+		DrawGroundSpriteAt(image, pal, _cur_ti->x, _cur_ti->y, _cur_ti->z, sub);
 	}
 }
 
@@ -472,7 +495,18 @@
 	_offset_ground_sprites = true;
 }
 
-static void AddCombinedSprite(SpriteID image, SpriteID pal, int x, int y, byte z)
+/**
+ * Adds a child sprite to a parent sprite.
+ * In contrast to "AddChildSpriteScreen()" the sprite position is in world coordinates
+ *
+ * @param image the image to draw.
+ * @param pal the provided palette.
+ * @param x position x of the sprite.
+ * @param y position y of the sprite.
+ * @param z position z of the sprite.
+ * @param sub Only draw a part of the sprite.
+ */
+static void AddCombinedSprite(SpriteID image, SpriteID pal, int x, int y, byte z, const SubSprite *sub)
 {
 	const ViewportDrawer *vd = _cur_vd;
 	Point pt = RemapCoords(x, y, z);
@@ -484,7 +518,7 @@
 			pt.y + spr->y_offs + spr->height <= vd->dpi.top)
 		return;
 
-	AddChildSpriteScreen(image, pal, pt.x - vd->parent_list[-1]->left, pt.y - vd->parent_list[-1]->top);
+	AddChildSpriteScreen(image, pal, pt.x - vd->parent_list[-1]->left, pt.y - vd->parent_list[-1]->top, false, sub);
 }
 
 /** Draw a (transparent) sprite at given coordinates with a given bounding box.
@@ -509,8 +543,9 @@
  * @param bb_offset_x bounding box extent towards negative X (world),
  * @param bb_offset_y bounding box extent towards negative Y (world),
  * @param bb_offset_z bounding box extent towards negative Z (world)
+ * @param sub Only draw a part of the sprite.
  */
-void AddSortableSpriteToDraw(SpriteID image, SpriteID pal, int x, int y, int w, int h, int dz, int z, bool transparent, int bb_offset_x, int bb_offset_y, int bb_offset_z)
+void AddSortableSpriteToDraw(SpriteID image, SpriteID pal, int x, int y, int w, int h, int dz, int z, bool transparent, int bb_offset_x, int bb_offset_y, int bb_offset_z, const SubSprite *sub)
 {
 	ViewportDrawer *vd = _cur_vd;
 	ParentSpriteToDraw *ps;
@@ -526,7 +561,7 @@
 	}
 
 	if (vd->combine_sprites == 2) {
-		AddCombinedSprite(image, pal, x, y, z);
+		AddCombinedSprite(image, pal, x, y, z, sub);
 		return;
 	}
 
@@ -585,6 +620,7 @@
 
 	ps->image = image;
 	ps->pal = pal;
+	ps->sub = sub;
 	ps->xmin = x + bb_offset_x;
 	ps->xmax = x + max(bb_offset_x, w) - 1;
 
@@ -613,7 +649,17 @@
 	_cur_vd->combine_sprites = 0;
 }
 
-void AddChildSpriteScreen(SpriteID image, SpriteID pal, int x, int y, bool transparent)
+/**
+ * Add a child sprite to a parent sprite.
+ *
+ * @param image the image to draw.
+ * @param pal the provided palette.
+ * @param x sprite x-offset (screen coordinates) relative to parent sprite.
+ * @param y sprite y-offset (screen coordinates) relative to parent sprite.
+ * @param transparent if true, switch the palette between the provided palette and the transparent palette,
+ * @param sub Only draw a part of the sprite.
+ */
+void AddChildSpriteScreen(SpriteID image, SpriteID pal, int x, int y, bool transparent, const SubSprite *sub)
 {
 	ViewportDrawer *vd = _cur_vd;
 	ChildScreenSpriteToDraw *cs;
@@ -642,6 +688,7 @@
 
 	cs->image = image;
 	cs->pal = pal;
+	cs->sub = sub;
 	cs->x = x;
 	cs->y = y;
 	cs->next = NULL;
@@ -1179,7 +1226,7 @@
 {
 	do {
 		Point pt = RemapCoords(ts->x, ts->y, ts->z);
-		DrawSprite(ts->image, ts->pal, pt.x, pt.y);
+		DrawSprite(ts->image, ts->pal, pt.x, pt.y, ts->sub);
 		ts = ts->next;
 	} while (ts != NULL);
 }
@@ -1250,10 +1297,10 @@
 		const ParentSpriteToDraw* ps = *psd;
 		const ChildScreenSpriteToDraw* cs;
 
-		if (ps->image != SPR_EMPTY_BOUNDING_BOX) DrawSprite(ps->image, ps->pal, ps->x, ps->y);
+		if (ps->image != SPR_EMPTY_BOUNDING_BOX) DrawSprite(ps->image, ps->pal, ps->x, ps->y, ps->sub);
 
 		for (cs = ps->child; cs != NULL; cs = cs->next) {
-			DrawSprite(cs->image, cs->pal, ps->left + cs->x, ps->top + cs->y);
+			DrawSprite(cs->image, cs->pal, ps->left + cs->x, ps->top + cs->y, cs->sub);
 		}
 	}
 }

--- a/src/viewport.h	Fri Oct 05 21:31:59 2007 +0000
+++ b/src/viewport.h	Fri Oct 05 21:49:15 2007 +0000
@@ -57,11 +57,11 @@
 
 void OffsetGroundSprite(int x, int y);
 
-void DrawGroundSprite(SpriteID image, SpriteID pal);
-void DrawGroundSpriteAt(SpriteID image, SpriteID pal, int32 x, int32 y, byte z);
-void AddSortableSpriteToDraw(SpriteID image, SpriteID pal, int x, int y, int w, int h, int dz, int z, bool transparent = false, int bb_offset_x = 0, int bb_offset_y = 0, int bb_offset_z = 0);
+void DrawGroundSprite(SpriteID image, SpriteID pal, const SubSprite *sub = NULL);
+void DrawGroundSpriteAt(SpriteID image, SpriteID pal, int32 x, int32 y, byte z, const SubSprite *sub = NULL);
+void AddSortableSpriteToDraw(SpriteID image, SpriteID pal, int x, int y, int w, int h, int dz, int z, bool transparent = false, int bb_offset_x = 0, int bb_offset_y = 0, int bb_offset_z = 0, const SubSprite *sub = NULL);
 void *AddStringToDraw(int x, int y, StringID string, uint64 params_1, uint64 params_2);
-void AddChildSpriteScreen(SpriteID image, SpriteID pal, int x, int y, bool transparent = false);
+void AddChildSpriteScreen(SpriteID image, SpriteID pal, int x, int y, bool transparent = false, const SubSprite *sub = NULL);
 
 
 void StartSpriteCombine();