ImageGear for C and C++ on Linux v20.0 - Updated
API Reference Guide > Core Component API Reference > Core Component Functions Reference > Image Processing Functions > IG_IP_rotate_any_angle_ex

This function rotates the image by the specified angle.


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AT_ERRCOUNT ACCUAPI IG_IP_rotate_any_angle_ex(
   HIGEAR hIGear,
   DOUBLE angle,
   AT_MODE rotate_mode,
   LPAT_PIXEL lpBkgrndColor,
   AT_MODE interpolation


Name Type Description
hIGear HIGEAR HIGEAR handle of image.
angle DOUBLE Angle by which to rotate the image, in degrees. Positive values result in clockwise rotation; negative values result in counter-clockwise rotation.
rotate_mode AT_MODE Rotation mode. Specifies whether the image should be clipped or expanded. See enumIGRotationModes for possible values.
lpBkgrndColor LPAT_PIXEL A far pointer to the RGB or pixel value that specifies the background color to be used in the displaced areas after the image has been rotated.
interpolation AT_MODE Interpolation to use for rotation. Supported modes are IG_INTERPOLATION_NONE, IG_INTERPOLATION_BILINEAR, IG_INTERPOLATION_BICUBIC. Ignored for 1-bit images.

Return Value:

Returns 0 if successful. Otherwise, returns the number of ImageGear errors that occurred during this function call.

Supported Raster Image Formats:


All pixel formats supported by ImageGear for C and C++, except:

Otherwise, all pixel formats supported by ImageGear for C and C++. 

Interpolation mode is ignored for 1-bit images.


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HIGEAR hIGear;            // HIGEAR handle of the image
AT_ERRCOUNT nErrcount;    // Count of errs on stack upon ret from func
AT_INT channelCount;    // Count of channels in the image
AT_PIXEL lpBackground[256];    // Buffer for background color

// Load image file "picture.bmp" from working directory
nErrcount = IG_load_file("picture.bmp", &hIGear);
if(nErrcount == 0)
    // Get channel count
    IG_image_channel_count_get(hIGear, &channelCount);
    // Initialize background color with '255'
    for(i = 0; i < channelCount; i ++)
        lpBackground[i] = (AT_PIXEL)255;
    nErrcount = IG_IP_rotate_any_angle_ex(hIGear, 45., IG_ROTATE_CLIP, lpBackground, IG_INTERPOLATION_BILINEAR);
    // ...
    // Destroy the image


The function rotates the image about its center point.

You can use IG_IP_rotate_compute_size to calculate the new dimensions of the bitmap that the image will have after rotation in IG_ROTATE_EXPAND mode.

For the highest quality, bilinear interpolation is recommended, especially if the rotation angle is small (less than 5 degrees) and/or the image will be rotated multiple times. Bi-cubic interpolation can be used to achieve a slightly sharper appearance.

Rotating the image multiple times at angles that are not multiple of 90 degrees may degrade the quality of the image.

You can only rotate PDF/PS images in 90 degree increments.

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