DrawBitmapOverFrame

TVideoGrabber.DrawBitmapOverFrame

Draws the bitmap passed as parameter over video frames.

Declaration
function DrawBitmapOverFrame (Bitmap: Graphics.TBitmap; LeftLocation: LongInt; TopLocation: LongInt; bmWidth: LongInt; bmHeight: LongInt; Transparent: Boolean; UseTransparentColor: Boolean; TransparentColorValue: TColor; AlphaBlend: Boolean; AlphaBlendValue: LongInt): Boolean;

bool __fastcall DrawBitmapOverFrame(Graphics::TBitmap *Bitmap, int LeftLocation, int TopLocation, int bmWidth, int bmHeight, bool Transparent, bool UseTransparentColor, TColor TransparentColorValue, bool AlphaBlend, int AlphaBlendValue)

Function DrawBitmapOverFrame(BitmapHandle As Long, LeftLocation As Long, TopLocation As Long, bmWidth As Long, bmHeight As Long, Transparent As Boolean, UseTransparentColor As Boolean, TransparentColorValue As Long, AlphaBlend As Boolean, AlphaBlendValue As Long) As Boolean

Description

Used to draw bitmaps over video frames.

Location
The bitmap is drawn at the LeftLocation, TopLocation position over the video frame (expressed in pixels).

Size
If the bmWidth or bmHeight parameter is different from the bitmap's width or height, the bitmap is stretched to bmWidth and bmHeight.

Transparency

- if the Transparent parameter is true, the image background is not drawn.

- f the Transparent parameter is true and the UseTransparentColor parameter is true, the TransparentColorValue value is used for transparency.

Alpha blending

If the AlphaBlend parameter is true, a progressive bitmap transparency is applied, depending of the AlphaBlendValue, in a 0..255 range.
It is not possible to perform alphablending when the Transparent parameter is true.
Important:
if the bitmap color format is not 32 bits, it will be converted into a 32 bit format. In other words, for better performance pass a bitmap already in 32 bits color format.

The DrawBitmapOverFrame function can be called ONLY from the OnFrameOverlayUsingDC event.
See the MainDemo project for sample code.