L_CreateBitmap

#include "l_bitmap.h"

L_LTKRN_API L_INT L_CreateBitmap(pBitmap, uStructSize, uMemory, uWidth, uHeight, uBitsPerPixel, uOrder, pPalette, uViewPerspective, pData, dwSize)

Initializes and allocates a bitmap, without loading any data.

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap to be created.

L_UINT uStructSize

Size in bytes, of the structure pointed to by pBitmap, for versioning. Use sizeof(BITMAPHANDLE).

L_UINT uMemory

Flags that indicate the type of memory to allocate. The following are valid values:

L_UINT uWidth

Width of the bitmap in pixels.

L_UINT uHeight

Height of the bitmap in pixels.

L_UINT uBitsPerPixel

The number of bits per pixel. Valid values are 0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 16, 24, 32, 48, and 64.

Use 0 to create an 8-bit grayscale bitmap. In that case, the function ignores the uOrder and pPalette parameters.

L_UINT uOrder

Color order for 16-, 24-, 32-, 48- and 64-bit bitmaps. If the resultant bitmap is less than 16 bits per pixel, this will have no effect since palletized images have no order. Possible values are:

L_RGBQUAD *pPalette

Pointer to the palette that the bitmap will use. You can specify your own palette, or use NULL for LEAD's fixed palette.

L_UINT uViewPerspective

Where the beginning of the image is stored. Most file formats start in the lower left corner while some formats start in the upper left corner. For valid values, refer to Accounting for View Perspective.

L_UCHAR* pData

Data pointer that will contain the bitmap data when uMemory is TYPE_USER. This data must be aligned on a four byte boundary. If pData is NULL, the data pointer must be passed later, by calling L_SetBitmapDataPointer, before the bitmap can be used.

L_SIZE_T dwSize

Size of the data buffer pointed to by pData. This should be at least pBitmap->Size. This parameter is only valid when uMemory is set to TYPE_USER.

Returns

Comments

Support for 12 and 16-bit grayscale images is only available in the Document and Medical Imaging toolkits.

You can specify 0 bits per pixel to create an 8-bit grayscale bitmap. In that case, the function ignores the uOrder and pPalette parameters.

Creating a bitmap of type TYPE_USER does not allocate memory for the bitmap. Instead, the data pointer pData is used.

There is some speed penalty (loss) for accessing tiled bitmaps. Therefore, it is not recommended for use with all bitmaps.

The tiled bitmaps are not used by default. LEADTOOLS will create them only if it failed to create conventional bitmaps and TYPE_NOTILED was not specified.

There are now three distinct types of bitmaps:

1. Conventional (uncompressed and contiguous) This is the most common type.

2. Compressed (1-bit only)

3. Tiled (uncompressed, stored internally as up to 64MB tiles)

If you pass TYPE_USER, you are responsible for freeing the bitmap data. L_FreeBitmap will not do this for you.

Some image processing functions, such as L_RotateBitmap and L_ColorResBitmap, need to re-allocate the image data. If you create a bitmap with TYPE_USER, and pass it to these functions, they will change the bitmap to TYPE_CONV and re-allocate the memory. Your original pData will no longer be used.

If the image is allocated as TYPE_DISK, then the image should not be used in multiple threads.

Required DLLs and Libraries

• LTKRN
• For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64, Linux.

L_INT CreateBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle for the final image */ 
   BITMAPHANDLE TmpBitmap;    /* Bitmap handle for the initial image */ 
   RGBQUAD      Palette[256]; /* Palette for the final image */ 
 
   /* Load a bitmap at 8 bits per pixel so that we can demonstrate palette handling */ 
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), &TmpBitmap, sizeof(BITMAPHANDLE), 8, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /* Load the new palette */ 
   nRet = L_GetBitmapColors(&TmpBitmap, 0, 256, Palette); 
   if(nRet !=SUCCESS) 
   { 
      L_FreeBitmap(&TmpBitmap); 
      return nRet; 
   } 
   /* Create the new bitmap */ 
   nRet = L_CreateBitmap(&LeadBitmap, sizeof(BITMAPHANDLE),TYPE_CONV, 
                        TmpBitmap.Width, 
                        TmpBitmap.Height, 
                        TmpBitmap.BitsPerPixel, 
                        TmpBitmap.Order, 
                        Palette, 
                        TmpBitmap.ViewPerspective, NULL, 0); 
   if(nRet !=SUCCESS) 
   { 
      L_FreeBitmap(&TmpBitmap); 
      return nRet; 
   } 
   /* Copy image data to the new bitmap */ 
   nRet = L_CopyBitmapData(&LeadBitmap, &TmpBitmap); 
   if(nRet !=SUCCESS) 
   { 
      L_FreeBitmap(&LeadBitmap); 
      L_FreeBitmap(&TmpBitmap); 
      return nRet; 
   } 
   /* Clean up */ 
   L_FreeBitmap(&TmpBitmap); 
   L_FreeBitmap(&LeadBitmap); 
   return SUCCESS; 
}