World: r4wp

This gets you reading and writing files, but you have to do any decoding 
yourself. So for reading JPEG data, you would probably write a binding 
to LibJPEG

If it doesn't need to be as specific as JPEG, you could write a binding 
to some wrapper library that supports multiple formats. For example, 
a simple BMP loading function is available for Red/System in the 
SDL binding:

http://red.esperconsultancy.nl/Red-SDL/dir?ci=tip

An example of loading an image is here in PeterPaint:

http://red.esperconsultancy.nl/Red-SDL/dir?ci=tip&name=examples

or xnview command line - then you just need a CALL ....

ah, wrong, I thought that you just need an image info, not actually 
an access to the bitmap data ...

There's also a basic binding to image loading in GDK, so that would 
load you all image types that GDK supports, including JPEG:

http://red.esperconsultancy.nl/Red-GTK/dir?ci=tip

GTK sounds like a winner.

Thanks for all the tips, guys!

For future reference, is it possible to use Red/System for commercial 
products?  Are there any restrictions?

Also, does anyone have an idea of how fast Red/System code is compared 
to comparable C code?

It's as fast as C core with the optimizer turned off, at least for 
now.

core -> code

Sorry for my ignorance, but how much faster is C with the optimizer 
turned on?  2x faster, 10% faster...?

No restriction for commercial use of binaries produced by Red and 
Red/System compilers.

Bo, in my tests, GCC produced twice as fast code with the regular 
optimisation of -O2. More than I thought

Bo, it depends on the code in question and the processor it's running 
on. It could be the same speed, it could be many times faster, and 
for some code it could be resolved completely at compile time and 
replaced with a constant.

We could run similar optimizations on Red/System code, as soon as 
we've implemented them.

Great!

Some optimizations will be very difficult or impossible to do if 
Red/System is used as the intermediate language, because those optimizations 
sometimes depend on the semantic model of the intermediate language, 
and Red/System doesn't have the semantic model of a compiler intermediate 
language. Optimization is hard work and people get PHDs for doing 
it. We can hope to catch up with modern C compilers, but don't expect 
it. One advantage is that Red is a high-level-enough language that 
an optimizer can make assumptions that a C compiler can't, so it 
is possible that we could get better code - it depends on the language 
and how much time we want to allocate on optimization.

I'm feeling nostalgic.  I used to hand-craft machine code on the 
6502/6510 series of processors back in the 80's, so I have an idea 
of what you're talking about.  There are some pretty neat tricks 
you can do when you're dealing with memory addresses directly.  I 
crafted more than one self-modifying program to squeeze every bit 
of computing power out of a processor.  I know that a lot of that 
ability has been removed by protected memory and abstraction, though.

Kaj, now that I've had a chance to do some work with Red/System, 
it's amazing to me how much work you've already done on adding features!


Here's something that I think would really help out a lot of us who 
want to make use of all your hard work.  Would it be hard to create 
http://red.esperconsultancy.nl/index.htmlwith a link to all the 
Red stuff you've done?  The only way I found what I needed to download 
was by searching through AltME for links, and had to manually enter 
in things like Red-common, Red-C-library, Red-cURL, Red-GTK, etc.

Thanks. A website is planned, but I haven't gotten around to it yet. 
I figure the time is better spent doing Red work

What I've done so far is the download.r script:

http://red.esperconsultancy.nl/Red-test/dir?ci=tip

If you combine it with Fossil, it will set up your entire environment 
automatically

It will also auto-update all bindings to new versions

Have you seen my 6502 emulator in Red/System yet? :-)

I saw that you wrote a 6502 emulator, but haven't had time to look 
at it yet.  Sounds like a fun project!

It is. :-) If you run the download.r script, you'll get it automatically

Recalling from the days when I didn't have an assembler, I had most 
of the decimal equivalents of the commands remembered because I input 
values into memory manually when I was writing code.  Going back 
in my brain 20 years, I believe LDA (Load the accumulator) was 169. 
:-)

So 'with in Red/System is like 'context in R2?

It's more like USE. CONTEXT exists as such in Red/System, but it's 
a compile time namespace instead of a runtime object

You first define a CONTEXT, then you can use it with WITH, or path 
notation

You're right about LDA #. :-) It's also $A9. I had the same problem, 
wrote a disassembler in Atari BASIC until I could get hold of an 
assembler, so also have a considerable part of my brain dedicated 
to such numbers :-)

With the following code:

#include %GTK.reds

with gdk [
	err: declare struct! [value [g/g-error!]]
	myimg: load-image "image.jpg" err
]

I get the following error:


*** Compilation Error: invalid literal syntax: [value [g/g-error!]]

If I change it to:

err: declare struct! [value [c-string!]]

I get the following error:


*** Compilation Error: argument type mismatch on calling: gdk/load-image

*** expected: [struct! [value [g/g-error!]]], found: [struct! [value 
[c-string!]]]

What am I missing?

You can't use path notation on types. I've been trying to coerce 
Doc into implementing that, but he doesn't want to. :-/

So you have to use an extra WITH g [...]. You can combine that as 
WITH [gdk g] [...]

Aha!  That did the trick!

By the way, if you only use images, you could do with including only 
GDK.reds. That would cut down on the dependencies

Instead of your struct definition, you can use g-error-reference! 
which is already defined in GLib.reds

There's an example of using load-image in GTK.reds in the icon function

Thanks!  When I use load-image, it looks like it is returning a pointer. 
 Is that correct?

For instance: 00DFD2B8

If 'load-image returns a pointer, how do I know when I have reached 
the end of the image?

Better yet, assuming 'load-image returns a pointer, how do I access 
the first memory location referenced by the pointer?

See the function spec in GDK.reds. It returns a pointer to an image! 
struct, so if you want to access the image internally, you have to 
go by that struct definition

As you can see in the same file, I haven't finished the definition 
of that struct, because I don't have to look inside the image