[sane-devel] Image Compression doesn't support in SANE protocal

[m. allan noah]

now that many low-end scanners support jpeg natively (some ONLY do jpeg!) 
i expect we will see more need for this.

as a short term fix, rather than adding a new sane_frame type, the backend 
can extract the compressed data, convert to raw bitmap. then frontend can 
convert to any compressed format it wants. this is not as efficient as 
keeping the compressed version the entire way through, but it works now.

dell networked scanner backend works this way.

allan

On Tue, 22 Aug 2006, zf wrote:

>    Yes, xsane can save file in a compressed format. But before that we must decompress the data from scanner and then transfer it to xsane and then xsane compress the image ....So we can't use the compressed data from scanner directly, then the scanner's speed is slow down.
>
> ----- Original Message -----
> From: "René Rebe" <rene at exactcode.de>
> To: "zf" <zfan333 at 163.com>
> Cc: "OrgSane-Devel at Lists. Alioth. Debian." <sane-devel at lists.alioth.debian.org>
> Sent: Tuesday, August 22, 2006 5:19 PM
> Subject: (ÈðÐÇÌáʾ-´ËÓʼþ¿ÉÄÜÊÇÀ¬»øÓʼþ)Re: [sane-devel] Image Compression doesn't support in SANE protocal
>
>
>> On Aug 22, 2006, at 8:10 AM, zf wrote:
>>
>>>  I found no image compression support is added in SANE. When
>>> scanning with high resolutions such 600 x 600 dpi and uses color
>>> scan, the result image will be very large!
>>>     So many scanners support compress transfer:scanner compress the
>>> image data and transfer compressed data to driver. In SANE the
>>> images transfered between backend and frontend are strict limited.I
>>> think it' better if SANE add some file transfer type like TWAIN.
>>
>> Most scanners do not support compression anyway. Such features are
>> only found in 5000 EUR and above devices. If you just want to save
>> files in a compressed format just use a decent application such as
>> xsane and not the example programs such as xscanimage ,-)
>>
>> Yours,
>>

-- 
"so don't tell us it can't be done, putting down what you don't know.
money isn't our god, integrity will free our souls" - Max Cavalera