Nestile - A tile editor for creating / editing NES graphics

1. Introduction and System Requirements

2. Using Nestile

3. Saving and Loading Tiles

4. Configuration Menu

5. Placeholders / Bugs

6. Contact / Credit

7. Introduction and System Requirements

Nestile is a tile editor created solely for editing graphics for NES programs. Better tile editors exist, but to my knowledge, none which are useable in Linux, which is the target platform of this program (although it should work in any OS which meets the requirements). It is useable both to create new files containing raw NES graphics data, or to directly edit files containing either raw NES graphics data or iNES formatted ROMs that store graphics in CHR-ROM.

To use the program, you will need to have Python installed on your machine.

2. Using Nestile

Run the file "nestile" with the file you want to open as an argument and the GUI will pop up. The long, skinny window with the File menu on it is the Tile Set window, the smallest window with the colors on the bottom is the Tile Editor window, and the other window is the Tile Layer window. When starting the program, all the windows should be blank.

The Tile Set window displays all the tiles in your ROM in monochrome, with black representing color 0, the brightest white representing color 3, and color 1 and 2 represented by the second darkest and second brightest shades of gray, respectively. By clicking on a tile in the Tile Set window, you choose which tile you want to edit in the Tile Editor window or paste onto the Tile Layer window. (Note: when I say color 0, 1, 2, 3, I mean that the pixels in the CHR-ROM file will be represented with the 2-bit value 0, 1, 2, or 3. Refer to information on the NES graphics format for more details).

The Tile Editor window is where you actually make changes to a tile. Click the colors to choose which color to draw with. The leftmost color represents color 0, the one to the right of it color 1, to the right of that color 2, and the rightmost represents color 3. Edit the tile by clicking the mouse on the Tile Edit screen. Edits you make here will show up in the Tile Set window as well as wherever you have the tile pasted in the Tile Layer window. You can change the color palette you are using by double clicking any of the colors to pull up the palette window. By clicking one of those colors, you assign that value to the currently selected color slot. This has no effect on how the data will be stored, so it's mostly for you to get an idea of what the graphics might look like (and you'll probably want to change it, since the default palette I apparently selected while I was drunk). The available palette is taken from freely available NES palettes (I forget whose, maybe Loopy's). One warning about changing palettes - the code for updating the color information is very, very hackish. Choosing a color which is extremely close in value to another color already selected in your palette may cause the tile to change any pixels in that already selected color to the newly selected color. I kind of doubt this is a practical problem, though, as I think the colors would have to be nearly indistinguishable, anyway. This is unlikely to be fixed unless someone emails me with a better way to update colors when the palettes are changed. Also, there is a bug where drawing while moving the mouse past the edge of the window will draw over onto the next tile over.

The Tile Layer window is where you can paste the tiles, to arrange them and get an idea of how they look when assembled. Clicking on the window will paste the currently selected tile to the Tile Layer window, in the 16x16 grid that you clicked on. The current palette is saved, so any changes to the palette in the Tile Layer window do not affect tiles which you have already pasted. This allows you to look at the same tile with different palettes and get an idea of which one will work best for you.

3. Saving and Loading Tiles

Files can be loaded in two different ways. The first way is to open a raw CHR-ROM file, in the same format saved as above. Again, this will only load the first 8192 bytes for now. The second way is to load an iNES format ROM image that has CHR-ROM data (about 3/4 of known NES roms do). Again, this is limited, as it will only load the first 8192 bytes of CHR-ROM. I may get around to bumping that up, though. In the meantime, if you want to look at the other data in an iNES ROM, either change the code in nestile (it actually wouldn't be too hard to do) or use a tool like "dd" to extract the raw data from the ROM (which is what I would do, because I am lazy)

Files can also be saved in one of two different ways, depending on how they were loaded. If no file was loaded, or a raw CHR file was loaded, the file will be saved as a raw CHR file. If the file was loaded from an iNES formatted file, then it will be saved as one. This means that you can use the program to edit the graphics in ROMs that have a CHR-ROM.

Something to note - the palette information is not saved in any form or fashion. That is there as an aid for you, but you'll be responsible for keeping up with the palette in your own programs.

4. Configuration Menu

The configuration menu is found under the "Edit" option of the menubar on the Tile Set window. This option lets you change the size of the CHR-ROM that you are currently working on. For the moment, this only works for raw CHR-ROM graphics - that is, if you open a iNES format ROM file, you can't change the size (although you can view it). This might change in the future. The size specified will be rounded up to the nearest multiple of 8192 bytes.

5. Placeholders / Bugs

Many of these are mentioned above, but I'll try to collect them all here for reference.

• Drawing past the edge of the window on the Tile Edit window will draw on the adjacent tile

• Changing a color in the palette to something very close to the a color already in the palette will change any pixels drawn in that color to the newly selected color, as well (this might not be a huge problem, unless you're doing something weird).

• You might have problems with the program if you run a color resolution other than 16-bit (maybe not, though - haven't tested it).

• Fix that you can't change two colors in the palette to the same color. This is to prevent the aforementioned bug where you could accidentally overwrite a color by selecting one similar to it.

• Add support for for left click and right click colors

• Add selection indicators for currently selected tiles and colors

• Split the view into a class separate from the tile data model

• Update README with new requirements and new screen shot

• Add scroll wheel support

• Make palette window modal or tied to which color is right clicked

• Add Tile Layout saving

• Add Tile Layout batch processing

• Add Tile Layout options to more accurately reflect PPU palettes

• Fix chr_rom_size logic

• Make nes_palette strings

• Add save/saveAs filename support

• Add support for specifying a file to open on the cmdline

6. Contact / Credit

This webpage for this program is http://ensomnya.net/projects/nestile/index.html Any updates made should be posted there.

Thanks to all the folks who worked on reverse-engineering the NES and creating freely available documentation for it. Thanks also to John Finlay for his PyGTK documents, which made it pretty easy to pick this library up and do something with it. Also thanks to Ted Kotz for overhauling the code to run on Python 3 and use Tkinter rather than PyGTK.

• Original Author : J. A. McMahan Jr.
• Major Update to Python 3 / Tkinter: Ted Kotz
• Version: See changes.txt for details on changes in different versions
• License: See license.txt for details, but it's a modified BSD license. By using this software, you agree to abide by the license.