+1 for editing sprites on GIMP
I find GIMP very very complicated and not at all intuitive ...
I'm not new to graphic editors, but a few days ago I spent almost 1 hour trying to make sense of the menus and options because I wanted to make a 16x16 sprite on a 32x32 canvas using a 2x2 pencil. And it did not work. Very very very frustrating ...
It seems to me the learning curve to be able to use GIMP properly is waaaayyyy too steep.
the problem with GIMP and any other modern gfx tools is that they are not fitted to msx graphics.
those tools are for contemporary era where you have millions of colors, shades, opacity ..... and others things possible.
msx screen modes, and sprite gfx have a lot of limitations, the colour clash, the one-color per line thing, the or-color weirdness... and a very limited palette of 15 colors...
drawing with a modern tool and doing a post-processing (convertion) is somewhat not comfortable.
A good sprite editor should have, for example the ability to choose two colors and automatically select the or-ed-color or the ability to fix the or-ed color and then choose the first and second color from the combinations that give the ored color, all this on a per sprite line-basis or for the entire one.
Another good option would be the ability to convert an existing 16x16 bitmap by choosing the best n-color combinations giving a maximum of number of colors x line.
By contrast, some useful functions that are a must in moderns gfx tools are less important in a sprite editor, for example, a flood fill function is not so a MUST when you are editing a small image of 16x16 pixels!
I use Aseprite, very nice pixel art editor, in combination with conversion tools.
Restrictions like colour clash and sprite rules I take into account myself, the converter will complain if I do it wrong.
Grauw, it sound interesting...
I make custom tools, it's not like a simple sprite editor is that complex to make. The difficulty with an or-compatible editor is that people have different ideas regarding the editing process. There are people who want to draw freehand and then reduce colors afterwards, and there are people who first want to set up the row colors and then design a sprite. Also, there are many games in which two sprites are alligned at the same spot. And then there are games where sprites are shifted here and there to result in bigger sprites with only or-colors in a smaller section in the center.
Also, how to deal with animations, like a walking figure? And are composite layers required? The editor itself isn't all that hard to do. Workflow, that's the thing here.
i think a good tool should help you in not doing mistakes not only complaining. ;-)
And the problem is always the same : it is uncomfortable to edit some gfx in a tool non msx-aware then converting and make corrections in my opinions.
just my cents
I must agree with Grauw and wolf_ ... Making an editor tool that will work with the OR color will probably frustrate some people because they would have handled the OR strategy differently. That part (converting to OR color) is more a part of the designer work than a straightforward automatic solution.
Having said that, we could imagine an agile editor which would allow many options to handle the OR color and satisfy everybody. But alas, that editor does not exist yet ...
In the same line of need, I'm also wanting a sprite editor that would handle 32x32 sprites overlapping by +1,+1 in order to be able to create good 32x32 sprite designs. It's really painstaking to do them manually.
Adding my Python 3 graphics conversion tools in this thread, even though they don't add anything new that hasn't been provided before: https://github.com/blihblah/jaassa under python/.
These read PNG files (I use GIMP to create these) and check the corresponding MSX1 colour from the palette map at the top of gfx_convert.py. I use this to create (uncompressed) data for sprites, characters and "the whole screen", but this ignores the screen's split into three 8-character rows.
produce_regular_gfx.py (which is called from generate_content.py) is an example on how to use it. The documentation is rather lacking, and it gives no warnings or errors if there are too many colours per 8x1 pixels.