From X-Plane SDK
There are a few built-in window styles in X-Plane that you can use.
Note that X-Plane 6 does not offer real shadow-compositing; you must make sure to put a window on top of another window of the right style to the shadows work, etc. This applies to elements with insets and shadows. The rules are:
Sub windows must go on top of main windows, and screens and list views on top of subwindows. Only help and main windows can be over the main screen.
With X-Plane 7 any window or element may be placed over any other element.
Some windows are scaled by stretching, some by repeating. The drawing routines know which scaling method to use. The list view cannot be rescaled in x-plane 6 because it has both a repeating pattern and a gradient in one element. All other elements can be rescaled.
WIDGET_API void XPDrawWindow( int inX1, int inY1, int inX2, int inY2, XPWindowStyle inStyle);This routine draws a window of the given dimensions at the given offset on the virtual screen in a given style. The window is automatically scaled as appropriate using a bitmap scaling technique (scaling or repeating) as appropriate to the style.
WIDGET_API void XPGetWindowDefaultDimensions( XPWindowStyle inStyle, int * outWidth, /* Can be NULL */ int * outHeight); /* Can be NULL */This routine returns the default dimensions for a window. Output is either a minimum or fixed value depending on whether the window is scalable.
Elements are individually drawable UI things like push buttons, etc. The style defines what kind of element you are drawing. Elements can be stretched in one or two dimensions (depending on the element). Some elements can be lit.
In x-plane 6 some elements must be drawn over metal. Some are scalable and some are not. Any element can be drawn anywhere in x-plane 7.
Scalable Axis Required Background
WIDGET_API void XPDrawElement( int inX1, int inY1, int inX2, int inY2, XPElementStyle inStyle, int inLit);XPDrawElement draws a given element at an offset on the virtual screen in set dimensions. EVEN if the element is not scalable, it will be scaled if the width and height do not match the preferred dimensions; it'll just look ugly. Pass inLit to see the lit version of the element; if the element cannot be lit this is ignored.
WIDGET_API void XPGetElementDefaultDimensions( XPElementStyle inStyle, int * outWidth, /* Can be NULL */ int * outHeight, /* Can be NULL */ int * outCanBeLit); /* Can be NULL */This routine returns the recommended or minimum dimensions of a given UI element. outCanBeLit tells whether the element has both a lit and unlit state. Pass NULL to not receive any of these parameters.
A track is a UI element that displays a value vertically or horizontally. X-Plane has three kinds of tracks: scroll bars, sliders, and progress bars. Tracks can be displayed either horizontally or vertically; tracks will choose their own layout based on the larger dimension of their dimensions (e.g. they know if they are tall or wide). Sliders may be lit or unlit (showing the user manipulating them).
ScrollBar - this is a standard scroll bar with arrows and a thumb to drag. Slider - this is a simple track with a ball in the middle that can be slid. Progress - this is a progress indicator showing how a long task is going.
WIDGET_API void XPDrawTrack( int inX1, int inY1, int inX2, int inY2, int inMin, int inMax, int inValue, XPTrackStyle inTrackStyle, int inLit);This routine draws a track. You pass in the track dimensions and size; the track picks the optimal orientation for these dimensions. Pass in the track's minimum current and maximum values; the indicator will be positioned appropriately. You can also specify whether the track is lit or not.
WIDGET_API void XPGetTrackDefaultDimensions( XPTrackStyle inStyle, int * outWidth, int * outCanBeLit);This routine returns a track's default smaller dimension; all tracks are scalable in the larger dimension. It also returns whether a track can be lit.
WIDGET_API void XPGetTrackMetrics( int inX1, int inY1, int inX2, int inY2, int inMin, int inMax, int inValue, XPTrackStyle inTrackStyle, int * outIsVertical, int * outDownBtnSize, int * outDownPageSize, int * outThumbSize, int * outUpPageSize, int * outUpBtnSize);
This routine returns the metrics of a track. If you want to write UI code to manipulate a track, this routine helps you know where the mouse locations are. For most other elements, the rectangle the element is drawn in is enough information. However, the scrollbar drawing routine does some automatic placement; this routine lets you know where things ended up. You pass almost everything you would pass to the draw routine. You get out the orientation, and other useful stuff.
Besides orientation, you get five dimensions for the five parts of a scrollbar, which are the down button, down area (area before the thumb), the thumb, and the up area and button. For horizontal scrollers, the left button decreases; for vertical scrollers, the top button decreases.