[sane-devel] Basic Image Buffering

[dio.rahman at gmail.com]

yes it is.

I will try to check it again.

But AFAIK the fwrite and memory copy like this would be the same.

On 2/3/09, m. allan noah <kitno455 at gmail.com> wrote:
> So if you output the image from your code to disk as a pnm, instead of
> handing it to opencv, does it look right?
>
> allan
>
> On Mon, Feb 2, 2009 at 9:03 PM,  <dio.rahman at gmail.com> wrote:
>> yeah -- it works; I use OpenCV to buffer the image -- with the size
>> the same as the param.pixels_per_line * param.line (width * height)
>>
>>
>>
>> On 2/3/09, m. allan noah <kitno455 at gmail.com> wrote:
>>> but when you use scanimage, it works?
>>>
>>> what image format are you saving it as?
>>>
>>> allan
>>>
>>> On Mon, Feb 2, 2009 at 8:41 PM,  <dio.rahman at gmail.com> wrote:
>>>> it's unsigned char
>>>> (unsigned char * imageData)
>>>>
>>>> as you can see in the scanimage example, in each loop the sane_read
>>>> will put the data into buffer with the specific buffer_size and actual
>>>> data length (len). Hence, in each loop we have to copy that "partial
>>>> image data" and assembly that data into the imageData.
>>>>
>>>> I also used that 'memcpy'
>>>>
>>>> while(status != SANE_STATUS_EOF){
>>>>                                status = sane_read (device, buffer,
>>>> buffer_size, &len);
>>>>
>>>>                                memcpy(imageData+offset,buffer,len);
>>>>                                offset+=len;
>>>>
>>>>                                 .....
>>>>
>>>> }
>>>>
>>>> and the problem still the same.
>>>>
>>>> Dio
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On 2/3/09, m. allan noah <kitno455 at gmail.com> wrote:
>>>>> what data type is imageData? why not memcpy instead?
>>>>>
>>>>> allan
>>>>>
>>>>> On Mon, Feb 2, 2009 at 7:43 PM,  <dio.rahman at gmail.com> wrote:
>>>>>> Dear all,
>>>>>>
>>>>>> I have a basic question on buffering the image.
>>>>>>
>>>>>> Suppose I have an image data pointer * imageData; and I have image
>>>>>> dimension information i.e. width and height.
>>>>>>
>>>>>> I need to copy the bytes read from the scanning process i.e. in the
>>>>>> buffer (sane_read(buffer,buffer_size,&len)) to the image data.
>>>>>>
>>>>>> So, I do:
>>>>>>
>>>>>> for(int i=0;i<len;i++)
>>>>>>    *(imageData++) = buffer[i]
>>>>>> until I found the SANE_STATUS_EOF
>>>>>>
>>>>>> but, when I showed the image, the pixel is not in the right order;
>>>>>> Anyone can help me?
>>>>>>
>>>>>> Thanks
>>>>>>
>>>>>> Dio
>>>>>> NOTE: I'm using CanonScan LiDE 50 -- grayscale image; and doing find
>>>>>> with the scanimage example
>>>>>>
>>>>>> --
>>>>>> sane-devel mailing list: sane-devel at lists.alioth.debian.org
>>>>>> http://lists.alioth.debian.org/mailman/listinfo/sane-devel
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>>>>>>             to sane-devel-request at lists.alioth.debian.org
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> "The truth is an offense, but not a sin"
>>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> "The truth is an offense, but not a sin"
>>>
>>
>
>
>
> --
> "The truth is an offense, but not a sin"
>