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 BITMAPHANDLE LUT and its Uses. If necessary, you can refer to the LTKRN.H header file, which describes the entire structure.
|uStructSize||L_UINT||Size of this structure in bytes, for versioning. Use the sizeof() macro 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.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.|
|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.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.|
|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:
|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.
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() macro 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.
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