Boost logo

Boost :

Subject: Re: [boost] [gil io_new review] Reading images fromin-memory sources
From: Domagoj Saric (domagoj.saric_at_[hidden])
Date: 2010-12-08 08:45:49

"Phil Endecott" <spam_from_boost_dev_at_[hidden]> wrote in message
> You're always reading 4 lines and asserting that rec_outbuf_height is not
> greater than this (as the docs say it will be). This is not unreasonably,
> but it's not exactly what I meant; in my code, I explicitly read exactly
> rec_outbuf_height lines.

Hmm, yes, this passage is definitely missing an implementation note :)
The assert is actually to be read the other way around, it is verifying that
I am providing enough scanlines for optimal reading (as recommended by the
documentation)...And the code does not actually read 4 lines, rather it
provides LibJPEG with the space to read up to 4 lines if it can/
is up to LibJPEG to decide how much to read...There is no need to read/use
the rec_outbuf_height value (unless you plan to dynamically allocate the
small scanlines buffer which would be self defeating) if the documentation
guarantees it will be between 1 and 4...

"What Huxley teaches is that in the age of advanced technology, spiritual
devastation is more likely to come from an enemy with a smiling face than
from one whose countenance exudes suspicion and hate."
Neil Postman 

Boost list run by bdawes at, gregod at, cpdaniel at, john at