* This file is part of OpenTTD.

 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.

 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.

 */

 *

 * \verbatim

 * The in-game coordinate system looks like this *

 *                                               *

 *                    ^ Z                        *

 *                    |                          *

	FOUNDATION_PART_NONE     = 0xFF,  ///< Neither foundation nor groundsprite drawn yet.

	FOUNDATION_PART_NORMAL   = 0,     ///< First part (normal foundation or no foundation)

	FOUNDATION_PART_HALFTILE = 1,     ///< Second part (halftile foundation)

	FOUNDATION_PART_END

};

 * @see StartSpriteCombine

 */

enum SpriteCombineMode {

	SPRITE_COMBINE_NONE,     ///< Every #AddSortableSpriteToDraw start its own bounding box

	SPRITE_COMBINE_PENDING,  ///< %Sprite combining will start with the next unclipped sprite.

	SPRITE_COMBINE_ACTIVE,   ///< %Sprite combining is active. #AddSortableSpriteToDraw outputs child sprites.

		y = vp->height - (_cursor.pos.y - vp->top);

	}

	/* Get the tile below the cursor and center on the zoomed-out center */

	return GetTileFromScreenXY(_cursor.pos.x, _cursor.pos.y, x + vp->left, y + vp->top);

}

 * of the viewport. This will update their status and invalidate accordingly

 * @param w Window pointer to the window that has the zoom buttons

 * @param vp pointer to the viewport whose zoom-level the buttons represent

 * @param widget_zoom_in widget index for window with zoom-in button

 * @param widget_zoom_out widget index for window with zoom-out button */

void HandleZoomMessage(Window *w, const ViewPort *vp, byte widget_zoom_in, byte widget_zoom_out)

		return;

	const ParentSpriteToDraw *pstd = _vd.parent_sprites_to_draw.End() - 1;

	AddChildSpriteScreen(image, pal, pt.x - pstd->left, pt.y - pstd->top, false, sub);

}

 * The bounding box extends from (x + bb_offset_x, y + bb_offset_y, z + bb_offset_z) to (x + w - 1, y + h - 1, z + dz - 1), both corners included.

 * Bounding boxes with bb_offset_x == w or bb_offset_y == h or bb_offset_z == dz are allowed and produce thin slices.

 *

 * @note Bounding boxes are normally specified with bb_offset_x = bb_offset_y = bb_offset_z = 0. The extent of the bounding box in negative direction is

 *       defined by the sprite offset in the grf file.

 *       However if modifying the sprite offsets is not suitable (e.g. when using existing graphics), the bounding box can be tuned by bb_offset.

	_vd.tile_sprites_to_draw.Clear();

	_vd.parent_sprites_to_draw.Clear();

	_vd.parent_sprites_to_sort.Clear();

	_vd.child_screen_sprites_to_draw.Clear();

}

 * If we do, the sprite memory will overflow. */

static void ViewportDrawChk(const ViewPort *vp, int left, int top, int right, int bottom)

{

	if (ScaleByZoom(bottom - top, vp->zoom) * ScaleByZoom(right - left, vp->zoom) > 180000) {

		if ((bottom - top) > (right - left)) {

			int t = (top + bottom) >> 1;

	w = GetCallbackWnd();

	if (w != NULL) w->OnPlaceObject(pt, TileVirtXY(pt.x, pt.y));

}

 * @param x       Desired x location of the map to scroll to (world coordinate).

 * @param y       Desired y location of the map to scroll to (world coordinate).

 * @param z       Desired z location of the map to scroll to (world coordinate). Use \c -1 to scroll to the height of the map at the \a x, \a y location.

 * @param w       %Window containing the viewport.

 * @param instant Jump to the location instead of slowly moving to it.

 * @return Destination of the viewport was changed (to activate other actions when the viewport is already at the desired position).

	if (tile != old) {

		if (tile != INVALID_TILE) MarkTileDirtyByTile(tile);

		if (old  != INVALID_TILE) MarkTileDirtyByTile(old);

	}

}

 * @param w Width of the highlighted tiles rectangle.

 * @param h Height of the highlighted tiles rectangle.

 */

void SetTileSelectSize(int w, int h)

{

	_thd.new_size.x = w * TILE_SIZE;

		/* draw the new selection? */

		if (_thd.new_drawstyle) SetSelectionTilesDirty();

	}

}

 * @param str String to be displayed

 * @param paramcount number of params to deal with

 * @param params (optional) up to 5 pieces of additional information that may be added to a tooltip

 */

static inline void ShowMeasurementTooltips(StringID str, uint paramcount, const uint64 params[])

{

static void VpStartPreSizing()

{

	_thd.selend.x = -1;

	_special_mouse_mode = WSM_PRESIZE;

}

 * The lower bits (0-3) are the track type. */

static HighLightStyle Check2x1AutoRail(int mode)

{

	int fxpy = _tile_fract_coords.x + _tile_fract_coords.y;

	int sxpy = (_thd.selend.x & TILE_UNIT_MASK) + (_thd.selend.y & TILE_UNIT_MASK);

	int fxmy = _tile_fract_coords.x - _tile_fract_coords.y;

			if (fxmy < -3 && sxmy > 3) return HT_DIR_VR;

			if (fxpy <= 12 && sxpy >= 20) return HT_DIR_HU;

			return HT_DIR_X;

	}

}

 * the dragging-style. Default directions are:

 * in the case of a line (HT_RAIL, HT_LINE):  DIR_NE, DIR_NW, DIR_N, DIR_E

 * in the case of a rect (HT_RECT, HT_POINT): DIR_S, DIR_E

 * For example dragging a rectangle area from south to north should be swapped to

 * north-south (DIR_S) to obtain the same results with less code. This is what

 * the return value signifies.

		default: NOT_REACHED();

	}

	return false;

}

 * Multiplies the result to suit the standard given by #TILE_HEIGHT_STEP.

 *

 * To correctly get the height difference we need the direction we are dragging

 * in, as well as with what kind of tool we are dragging. For example a horizontal

 * autorail tool that starts in bottom and ends at the top of a tile will need the

 * maximum of SW, S and SE, N corners respectively. This is handled by the lookup table below