BITMAPHANDLE

The BITMAPHANDLE structure serves as a working area for image manipulation and conversion. LEADTOOLS functions use this structure as a bitmap handle for accessing the image in memory and for maintaining the characteristics of the image.

Note:

Fields intended for internal use, such as the pointer to the bitmap, are omitted from the table. If necessary, you can refer to the LTKRN.H header file which describes the entire structure.

Member	Data Type	Description
Width	L_INT	Image width in pixels.
Height	L_INT	Image height in pixels.
BitsPerPixel	L_INT	Number of bits per pixel.
BytesPerLine	L_UINT	Bytes per line, rounded upward to the nearest multiple of four.
Flags.Allocated	L_BITFIELD	TRUE if the bitmap is allocated.
Flags.ConventionalMemory	L_BITFIELD	TRUE if the bitmap is allocated using conventional memory.
Flags.DiskMemory	L_BITFIELD	TRUE if the bitmap is allocated using LEAD's own virtual memory.
Flags.LockedMemory	L_BITFIELD	TRUE if the bitmap memory is locked down.
Flags.Progressive	L_BITFIELD	TRUE if an image is being loaded from a progressive JPEG file.
Flags.Tiled	L_BOOL	TRUE if the bitmap is a tiled bitmap.
Flags.WaitUserInput	L_BITFIELD	TRUE if the animation playback waits for user input.
Flags.Transparency	L_BITFIELD	TRUE if the animation playback uses transparency.
Flags.Compressed	L_BITFIELD	TRUE if the current bitmap is in 1-bit RLE-compressed format. For information about this format, refer to Speeding Up 1-Bit Documents.
Flags.Signed	L_BITFIELD	TRUE if the pixel values in the bitmap are signed.
nColors	L_INT	Number of colors (256 or less) that the bitmap has. If the image has more than 256 colors, this value is zero.
hPalette	HPALETTE	Handle to the image's palette. It can be an optimized palette or a fixed palette.
ViewPerspective	L_CHAR	Where the beginning of the image is stored. Valid values are TOP_LEFT, BOTTOM_LEFT, TOP_RIGHT, BOTTOM_RIGHT, TOP_LEFT90, and TOP_LEFT270. For descriptions, refer to Accounting for View Perspective.
Order	L_INT	Color order of the bitmap. Possible values are ORDER_RGB, ORDER_BGR and ORDER_GRAY.
Size	L_UINT32	Size of the bitmap image data, in bytes.
DitheringMethod	L_UINT	Dithering method (referenced by some functions). For possible values, refer to the L_DefaultDithering function.
XResolution	L_INT	Horizontal resolution, in dots per inch. Some file formats save this value in the file header.
YResolution	L_INT	Vertical resolution, in dots per inch. Some file formats save this value in the file header.
Left	L_INT	Left offset for animation playback.
Top	L_INT	Top offset for animation playback, based on a TOP_LEFT view perspective.
Delay	L_UINT32	Animation playback delay in milliseconds (ms).
Background	COLORREF	Background color for animation playback. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.
Transparency	COLORREF	Transparent color for animation playback. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.
DisposalMethod	L_UINT	Animation playback disposal method. For possible values, refer to Animation Disposal Methods.
LowBit	L_INT	Value indicating the low bit used for window leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale). A value of -1 will be treated as 0.
HighBit	L_INT	Value indicating the high bit used for window leveling. 0 <= nLowBit <= nHighBit <= (11 for 12-bit grayscale or 15 for 16-bit grayscale). A value of -1 will be treated as BitsPerPixel -1.
MinVal	L_INT32	Minimum grayscale value. For every value between 0 and MinVal, Black (RGB(0,0,0)) will be used. For values between MinVal and MaxVal, the gray value to be displayed is calculated by : gray = (index - MinVal) * 255 / (MaxVal - MinVal).(See * below)
MaxVal	L_UINT	Maximum grayscale value. For every value larger than MaxVal, White (RGB(255,255,255)) will be used. For values between MinVal and MaxVal, the gray value to be displayed is calculated by : gray = (index - MinVal) * 255 / (MaxVal - MinVal). (See * below)

* Index is the intensity value of the pixel. If the intensity value is > MaxVal, the color will be White. If the intensity value is < MinVal, the color will be Black. For those intensity values between MinVal and MaxVal, the above equation is used to determine the color, with index equal to the intensity value.

Comments

pBITMAPHANDLE is a pointer to a BITMAPHANDLE structure. Generally, where a function parameter type is pBITMAPHANDLE, you can declare a BITMAPHANDLE variable, update the structure's fields, and pass the variable's address in the parameter. Declaring a pBITMAPHANDLE variable is necessary only if your program requires a pointer.

In most cases, the values of fields in the BITMAPHANDLE structure are maintained by LEADTOOLS functions.

Note: A 16-bpp image may be color or grayscale. If you are working with a 16-bit grayscale image, explicitly set BITMAPHANDLE.Order to ORDER_GRAY. By default, the Order for a 16-bit image will be set to ORDER_BGR.

Please note that tiled bitmaps will have Flags.ConventionalMemory set, since the bitmap is allocated in conventional memory. To determine whether a bitmap is "regular memory", do the following:

if (!pBitmap->Flags.Compressed && !pBitmap->Flags.Tiled)
{
//regular bitmap. It is not compressed and it is not tiled.
}