This function provides information about a rectangular area of the image.
Declaration:
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AT_ERRCOUNT ACCUAPI IG_IP_area_info_get(
HIGEAR hIGear,
const LPAT_RECT lpRect,
HIGPIXEL lpPixel,
AT_MODE nChannel,
AT_MODE nInfo
);
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Arguments:
| Name | Type | Description |
| hIGear | HIGEAR | Handle of the image for which to obtain the information. |
| lpRect | const LPAT_RECT | Rectangle to get the information from (pass NULL for getting information on the whole image). |
| lpPixel | HIGPIXEL | Receives the calculated value. Depending on the "DIB.PIX_ACCESS_USE_LEGACY_MODE" global control parameter - either a HIGPIXEL object handle, or a pointer to an array of AT_PIXEL. See Remarks. |
| nChannel | AT_MODE | Specifies a channel or a channel range to get the info about. See enumIGColorChannels for possible values. |
| nInfo | AT_MODE | Specifies the kind of information to be obtained. See enumDIBAreaInfo for possible values. |
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 Professional.
Sample:
Pixel Access, Legacy Pixel Access
Example:
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HIGEAR hIGear; // HIGEAR handle of image AT_ERRCOUNT nErrcount; // Count of errs on stack upon ret from func AT_INT channelCount; // Count of channels in the image AT_INT bitsPerChannel; // Channel depth HIGPIXEL hPixel; // Load image file "picture.bmp" from working directory nErrcount = IG_load_file("picture.bmp", &hIGear); if(nErrcount == 0) { // Set IG_PIX_ACCESS_MODE_NEW access mode AT_LMODE AccessMode = IG_PIX_ACCESS_MODE_NEW; IG_gctrl_item_set("DIB.PIX_ACCESS_USE_LEGACY_MODE", AM_TID_AT_LMODE, &AccessMode, sizeof(AT_LMODE), NULL); IG_image_channel_count_get(hIGear, &channelCount); IG_image_channel_depth_get(hIGear, 0, &bitsPerChannel); hPixel = IG_pixel_create(channelCount, bitsPerChannel); if(hPixel != NULL) { // Get average pixel value nErrcount = IG_IP_area_info_get(hIGear, NULL, hPixel, IG_COLOR_COMP_ALL, IG_DIB_AREA_INFO_AVE); // ... // Delete pixel IG_pixel_delete(hPixel); } // Destroy the image IG_image_delete(hIGear); } |
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Remarks:
Behavior of this function depends on the "DIB.PIX_ACCESS_USE_LEGACY_MODE" global control parameter.
If "DIB.PIX_ACCESS_USE_LEGACY_MODE" is set to IG_PIX_ACCESS_MODE_NEW, the function expects that lpPixel is set to an HIGPIXEL object handle. The calculated value will be returned in this object. Use IG_pixel_create to create an HIGPIXEL object, specifying the correct number of channels and number of bits per channel. Use IG_pixel_delete to delete it when it is no longer in use.
If the global parameter is set to IG_PIX_ACCESS_MODE_LEGACY, the function expects that lpPixel is a pointer to an array of AT_PIXEL. Length of the array must correspond to the number of image channels. The area info will be scaled to the AT_PIXEL range (BYTE). For example, if the image has 16 bits per channel, and the area info corresponds to 32767, the return value will be (32767 / 256) = 128.
See Pixel Access Modes section for more information on pixel access modes.
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Default value of "DIB.PIX_ACCESS_USE_LEGACY_MODE" global control parameter is IG_PIX_ACCESS_MODE_LEGACY. |