| LEADTOOLS Raster Imaging C DLL Help > Function References > L_TunnelBitmap | 
#include "l_bitmap.h"
L_LTIMGSFX_API L_INT L_TunnelBitmap(pBitmap, ptCenterPoint, uZValue, nDistance, uRad, nRepeat, nRotationOffset, uStretch, uStartBright, uEndBright, uBrightLength, crBright, crFill, uFlags)
| pBITMAPHANDLE pBitmap; | /* pointer to the bitmap handle */ | 
| POINT ptCenterPoint; | /* point at which the viewer is looking */ | 
| L_UINT uZValue; | /* viewing screen offset on the Z-axis */ | 
| L_INT nDistance; | /* camera distance from the viewing screen */ | 
| L_UINT uRad; | /* tunnel radius */ | 
| L_INT nRepeat; | /* number of times the bitmaps are repeated */ | 
| L_INT nRotationOffset; | /* rotation offset */ | 
| L_UINT uStretch; | /* compression factor */ | 
| L_UINT uStartBright; | /* brightness of an external light source on the first bitmap displayed */ | 
| L_UINT uEndBright; | /* brightness of an external light source on the last bitmap displayed */ | 
| L_UINT uBrightLength; | /* changes in brightness along the Z axis */ | 
| COLORREF crBright; | /* color of an external light source that is shined on the bitmaps */ | 
| COLORREF crFill; | /* background color */ | 
| L_UINT uFlags; | /* flags */ | 
Places the bitmap inside a tunnel along the Z-axis.
| Parameter | Description | |
| pBitmap | Pointer to the bitmap handle referencing the bitmap to be changed. | |
| ptCenterPoint | POINT structure that contains the point at which the camera or viewer is looking. It may be outside the bitmap borders. | |
| uZValue | Viewing screen offset on the Z-axis, in pixels. | |
| nDistance | Camera distance from the viewing screen, in pixels. | |
| uRad | Tunnel radius. | |
| nRepeat | Number of times the bitmap repeats along the Z-axis. If nRepeat equals 1 the bitmap will be infinitely repeated. Its range starts from 1. | |
| nRotationOffset | Rotates tunnel around the Z-axis in pixel steps. If TUN_AXIS_WIDTH option is selected then the bitmap width is along the Z-axis and nRotationOffset set to the bitmap height is equivalent to a complete cycle. If TUN_AXIS_HEIGHT option is set, then the bitmap height is along the Z-axis and nRotationOffset set to the bitmap width is equivalent to a complete cycle. | |
| uStretch | Value that indicates whether to expand or compress the bitmap, and by how much. If uStretch < 100 bitmap will be expanded. If uStretch > 100 the bitmap will be compressed. Use 100 to maintain the bitmap's dimensions. The value of this parameter is internally divided by 100. | |
| uStartBright | Value that indicates the brightness of an external light source at the beginning of the tunnel. Possible values range from 0 to 100. A value of 0 indicates no external light is displayed at the beginning of the tunnel. A value of 100 indicates an external light source with full brightness is displayed. | |
| uEndBright | Value that indicates the brightness of an external light source at the end of the tunnel. Possible values range from 0 to 100. A value of 0 indicates no external light displayed at the end of the tunnel. A value of 100 indicates an external light source with full brightness is displayed on the bitmap. | |
| uBrightLength | Value that indicates how much the brightness changes as you move along the Z axis. This parameter is internally multiplied by 50. | |
| crBright | The COLORREF value that specifies the color of an external light source that shines in the tunnel. | |
| crFill | The COLORREF value that specifies the background color. | |
| uFlags | Flags that indicate the background color and which bitmap dimension extends along the Z-axis. You can use a bit wise OR (|) to specify one flag from each group. | |
| 
 | The following are the flags that indicate the background color: | |
| 
 | Value | Meaning | 
| 
 | PLANE_FILL_CLR | [0x0001] Use the crFill as a background color. | 
| 
 | PLANE_NO_CHG | [0x0002] Use the image itself as a background. | 
| 
 | The following are the flags that indicate which bitmap dimension is along the Z-axis: | |
| 
 | Value | Meaning | 
| 
 | TUN_AXIS_WIDTH | [0x0010] Bitmap width will be along the Z-axis. | 
| 
 | TUN_AXIS_HEIGHT | [0x0020] Bitmap height will be along the Z-axis. | 
| 
 | Value | Meaning | 
| 
 | TUN_FILL_CLR | [0x0001] Fill any exposed areas with crFill. | 
| 
 | TUN_NO_CHG | [0x0002] Leave the exposed area as is, without changing it. | 
Returns
| SUCCESS | The function was successful. | 
| < 1 | An error occurred. Refer to Return Codes. | 
Comments
This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.
This function shows the effect of placing a bitmap inside a tunnel along the Z-axis. An external light source of the specified color and brightness may be shined on the bitmaps. The brightness may vary along the z-axis according to the uBrightLength value.
Changing the camera center point, the rotation angle and the viewing screen Z-offset will simulate moving along the axis.
If the bitmap has a region, the effect will be applied on the region dimensions only.
This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.
To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.
For an example, see the following figure:

The following figure shows the same bitmap, after the effect has been applied:

To obtain this effect, the following settings were used with the function:
CenterPoint(x,y) = (200,200)
uZValue=  0
nDistance= 200
uRad= 200
nRepeat= -1
nRotationOffset= 195
uStretch=  25
uStartBright= 0
uEndBright= 100
uBrightLength= 45
crBright= RGB(255,255,255)
crFill= RGB(255,255,255)
uFlags= PLANE_FILL_CLR | TUN_AXIS_WIDTH
This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.
Required DLLs and Libraries
| 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.
See Also
Example
#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName
 L_INT TunnelBitmapExample(L_VOID)
{
   L_INT nRet;
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle for the image */
   POINT CenterPt; 
   /* Load a bitmap at its own bits per pixel  */
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
   if(nRet !=SUCCESS)
      return nRet;
   /* put the image inside tunnel with its width along the Z-axis*/
   CenterPt.x  =  LeadBitmap.Width/2;
   CenterPt.y  =  LeadBitmap. Height/2;
   nRet = L_TunnelBitmap(&LeadBitmap, CenterPt, 0, LeadBitmap.Height, LeadBitmap.Width/2, -1,0, 25,0,100, 20000, RGB(255,0,0), RGB(0,0,0),TUN_AXIS_WIDTH | PLANE_FILL_CLR);
   if(nRet !=SUCCESS)
      return nRet;
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL);
   if(nRet !=SUCCESS)
      return nRet;
   //free bitmap 
   if(LeadBitmap.Flags.Allocated)  
      L_FreeBitmap(&LeadBitmap);  
   return SUCCESS;
}