Android Question Create Grid on which to draw upon

[lock255]

I would like to create a grid where I can get the coordinates of each point (kind of a sheet of squared paper), so that I could connect to the lines and then create a design.
Anyone have any suggestions that can help me to solve the problem?

 

[klaus]

You can draw the grid onto the activity or a panel.
Use another panel for the drawing and with the Touch event of this panel you get the current position of the touch point and calculate the the equivalent grid coordinate and draw with these coordinates.

 

[lock255]

What I would, but I need to know:

1. How do I draw the grid on the panel?
   
2. If a device with a smaller screen or larger, the grid is resized, but I need the coordinates to the points of intersection in the grid remain the same.

 

[klaus]

You need to give some more details.
Do you want to draw different types of objects like line, rectangle, oval, circle etc and memorize them ?
This looks like a small CAD program.

 

[lock255]

I would like to create a map with a grid background that looks like a sheet of paper.
I would like to point out that this is a game, above the map I would like to create a circuit (with straight roads and curves, created with simple lines).
I found an example of what I would do (graphically): http://upload.wikimedia.org/wikibooks/it/2/20/Gran_premio.png

 

[klaus]

Attached you find a small drawing program with a grid.
It's not exactly what you are looking for but you can see the principle.

 

[lock255]

Is a wonderful example! I'll try to work on this

 

[lock255]

You can explain a few things the example you gave me attached:

1. How can I remove the function of the oblique line?
2. If I wanted to find the coordinates of a point as I do?

 

[klaus]

How can I remove the function of the oblique line?

I suppose you mean having a 'cursor' function.
If you mean deleting a drawn object, this will first need:
- Defining drawing objects and memorizing them with their properties in a list.
And then to delete an object:
- Remove the object from the list and redraw the whole drawing.

Attached you find a new version.
- Added a cursor function showing a cursor and its coordinates.
- Added a delete function which deletes the whole drawing.

 

[lock255]

1. Wow the cursor works fine, you're a magician!
2. I did not mean to delete the entire design but two buttons, which allow you to go back and forth with the modiriche (like in a browser or CAD editing)
3. I would like to put a button that draws only straight horizontal and veticali (no oblique lines). What I wish is that possible?

 

[klaus]

You should do the next steps of the program yourself, with the example programs have the basic principles.
3. This is relatively easy, based on the oblic line drawing you can adapt it for horizontal and vertical lines.
2. This a bit more complicated.
You must define what exactly you want, because the principle may be different according to what you need.
- Memorizing only the bitmap or memorizing also the object type and its properties.