IG_IP_rotate_any_angle

IG_IP_rotate_any_angle_ex

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This function rotates the image by the specified angle.

Declaration:

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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 );

Arguments:

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:

If interpolation is IG_INTERPOLATION_BILINEAR or IG_INTERPOLATION_BICUBIC:

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

Indexed RGB with non-grayscale palette.
Images that have a Grayscale LUT attached to them.

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

Interpolation mode is ignored for 1-bit images.

Sample:

See GUI component source code.

Example:

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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 AT_INT i; // 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 IG_image_delete(hIGear); }

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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
AT_INT i;

// 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
    IG_image_delete(hIGear);
}

Remarks:

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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