The next problem I'm considering here is the background image's relationship to a saved map.

The idea here is that we've started the process of creating a new map from an image, and now we want to save our work and come back to it later.

We can save the background image and the settings (top/left/scale) in the map file.

The alternative is to expect the user to load the background image with the same settings next time.

One restraining factor here is that we don't have save-files for the editor, and save-files for games.  They are the same, except the saved-game files contain more information.  The background image stuff is intended specifically for the scenario editor as a tool for setting tiles on the map.

Now imagine that the background image isn't just used as a background image for editing purposes, it is the map to be displayed underneath tiles during a game.  This allows for large finely drawn maps in the game (e.g. remember the transparent cities from an earlier post.)

If we go with that feature, it means that the background image should be part of the saved map, and drawn before any of the tiles are drawn.

A side effect of this approach is that the background image is retained in the saved game file, even if it is completely covered by tiles.

Perhaps.  And after that it would be easier to make the picture box draggable.  And after that, the mouse wheel could be attached to the scale button.

Isn't it reasonable to presume that the user has a picture of a map that they're comfortable with?

Other parts of the scenario editor presume the user has basic command of an image editor.

On the other hand I can imagine an average user bringing in a horizontally rectangular image, and then expecting to get the center of it on a vertically rectangular map.  I would guess that most map images are horizontally rectangular or are square.

I've hacked something up for the "new map" portion of this task.
http://www.dailymotion.com/video/xe547y_lordsawar-making-a-new-map-from-an_videogames

What do you think?

I had the gimp's resize canvas dialog in mind.

I'm not going to make it as interactive though.  e.g. no clicking and dragging on the overlapping boxes.

I'm imagining a dialog where you give it the background image, and then it automatically guesses the tile dimensions and image scale.

It should be able to change the tile dimensions to anything you want.  Also it should be able to change the dimensions to the "normal" size, the "small" size, or the "tiny" map size.

It should also be able to change the scale of the background image.

The relationship of the background image to the map size should be displayed in a way that makes it clear which part of the background image is on the map, and which isn't.

Questions:

Would the background image be stretched to fit the map?

I expect your answer to that is no.

Maybe it would make more sense to add it to new map somehow.  This would allow the miniature map can have the right number of tiles.

What do you think?

I have also thought of this feature, but I haven't implemented it yet.

I want to add: "File->Import Background" to the scenario editor.  It would scale the image to be the right size, and then cut it up into tilesized pieces.

Three reasons I haven't done this already are:
1. Because it would grow the tarball by a lot,
2. I don't have an appropriately licensed background image,
3. WL2 didn't let you do this.

You could even have blank city images, and rely on the background image to give you different looking cities.  Or perhaps other than blank, you could have a few player-coloured flags sticking up out of the ground.  And for razed cities the raze image would just be some localized fires.