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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. For instance, pLUT, pLUT16, PaintLowBit and PaintHighBit are all members that are useful when window-leveling. For more information about using these members when displaying images or performing image processing, refer to Lookup Table (LUT) in BITMAPHANDLE and its use for Displaying Images and Performing Image Processing. If necessary, you can refer to the LTKRN.H header file, which describes the entire structure.

Member

Data Type

Description

uStructSize L_UINT Size of this structure in bytes, for versioning. Use the sizeof() operator to calculate this value.
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.ProgressiveAvailable L_BITFIELD TRUE if an image is being loaded from a progressive file (i.e. Progressive JPEG).
Flags.LockedMemory L_BITFIELD TRUE if the bitmap memory is locked down.
Flags.Interlaced L_BITFIELD TRUE if an image is being loaded from an interlaced file (i.e. Interlaced GIF).
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.
Flags.Mirror L_BITFIELD TRUE if the bitmap is a mirror of another bitmap.
Flags.UseLUT L_BITFIELD TRUE if the LUT is used in all image processing functions, including save. FALSE if the LUT is used only when painting. If this is FALSE, the LUT is ignored when an image processing function is applied or when a file is saved.
Flags.Global L_BITFIELD Internal use only.
Flags.UsePaintLUT L_BITFIELD TRUE to use PaintGamma, PaintContrast, PaintIntensity when painting.
Flags.Tiled L_BITFIELD TRUE if the bitmap is a tiled bitmap.
Flags.SuperCompressed L_BITFIELD TRUE if the bitmap is in super compressed format. The bitmap can be 24-bit or 1-bit. For more information, refer to Super Compressed Bitmaps.
Flags.NoClip L_BITFIELD Internal use only.
Flags.PremultiplyAlpha L_BITFIELD TRUE if the data is premultiplied with the alpha (for 32-bit bitmaps).
Flags.NonLinearLUT L_BITFIELD TRUE if the LUT is non-linear (for 12/16-bit grayscale bitmaps).
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.
pPalette L_RGBQUAD* Array of palette colors.
ViewPerspective L_INT 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
ORDER_GRAY
ORDER_RGBORGRAY
ORDER_BGRORGRAY
ORDER_ROMM
ORDER_BGRORGRAYORROMM
ORDER_RGB565
Size L_UINT32 Deprecated, use the Size64 member.
Size64 L_UINT64 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.

Some functions which take this structure as a parameter require that the structure be initialized prior to the function call. You must set the uStructSize member to the total size, in bytes, of the structure. Use the sizeof() operator to calculate this value. Functions that do not require the structure be initialized will take the total size of the structure, in bytes, as an additional function parameter.

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. 
} 

Support for super compressing bitmaps is available in the Document and Medical Imaging toolkits.

When Flags.NonLinearLUT is set to TRUE, the LEADTOOLS resample functions will resample the LUT index. This is the preferred mechanism for DICOM images. However, if the LUT is not linear (for example if some LUT portions contain some colors while others have grayscale values), painting artifacts might be produced when operating on the index. If the LUT is not linear, LEADTOOLS converts the image data to color 24-bit when painting by using the LUT and then performs the resample/bicubic resize on the 24-bit data. LEADTOOLS sets this value to TRUE automatically when loading DICOM files that contain a 16-bit palette. You should set this to TRUE if you change the LUT manually, or if you change the LUT to be non-linear. Warning: Failure to set this value properly can cause problems with displaying zoomed bitmaps when paint mode is set to resample/bicubic.

References

BITMAPHANDLE LUT and its Uses

L_WindowLevel

L_WindowLevelExt

L_ApplyLinearVOILUT

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