How do I start creating a paint app?

Questions
1

I’ve been trying to examine the examples on the Codea app to learn how to add the touch feature, but I’m having trouble. The touch feature’s code seems to vary, depending on what you use it for. Also, I’m not finding very many examples on how to set up the program when touch code is involved. Please, at least help me figure out how to make a simple menu with empty spots for the tool icons. Thanks if you do.

2

@VersatileAlien I gave you an example of using touch in your previous discussion. Programming isn’t exact, everything you do will vary based on what you want to do. You want to create a paint app, but there are many different ways based on what you want it to do. If you know nothing about programming, then you’re going to have a hard time. If you know something about programming, then you’ll still have a hard time. It takes time and a lot of learning to easily write a program. You want to make a simple menu with empty spots for the tool icons. That still doesn’t give much information. What kind of menu do you want and what kind of tool icons are you going to create. Also, what have you done on your own so far. I’ll post a simple paint program example as soon as I write it.

3

Here’s a simple paint program. You can change the color and the line size. Tap the < in the upper left to hide/show the parameter pane for full screen drawing. This should give you an idea of what you might want to do.

displayMode(OVERLAY)

function setup()
    background(0)
    backingMode(RETAINED)    
    x1,y1=-10,-10
    x2,y2=x1,y1
    parameter.color("col",255,0,0)
    parameter.integer("size",1,30,5)
    stroke(col)
    strokeWidth(size)
end

function draw()
    line(x1,y1,x2,y2) 
    x2,y2=x1,y1   
end

function touched(t)
    if t.state==BEGAN then
        stroke(col)
        strokeWidth(size)
        x1,y1=t.x,t.y
        x2,y2=x1,y1       
    end
    if t.state==MOVING then
        x1=t.x
        y1=t.y
    end
end
4

Thanks. The last touch example didn’t seem to work for me, but this one did. Maybe I didn’t put it in right, or something. Codea doesn’t exactly tell you what you should do first. It just has a getting started button on the bottom of the screen and expects you to know where and what to do from there.

I’m sorry, but I don’t know whether to use FAQ, tutorials, the syntax library, or what. Besides, I’m a visual person who likes using tutorials and experimenting. I’m also someone who needs examples to see patterns and make connections. Seeing patterns helps me understand what I’m doing and the logic behind it.

Codea doesn’t exactly give a complete list of every known programming term and what they mean or are used for right at your fingertips so you can play around with them. Anyways, thanks for the help.

5

@VersatileAlien Codea seems to be geared towards people that know at least a little about programming. How much experience at programming do you have. If you tap the Wiki link at the top of the forum, you’ll find a lot of info there that should help. If you have more questions, we’re here to help. You can also copy and paste examples from the forum into a project if you want to run forum examples to play around with.

6

There have been quite a few paint app projects, if you search the forum

More generally, a paint app is probably too advanced to start with, because it doesn’t play to Codea’s main strength, which is animated graphics, ie moving pictures, like games. Putting stuff on the screen that just sits there, and recording finger movements to draw lines, isn’t as intuitive and easy as making stuff move around the screen.

In any event, I suggest the way to get started is to learn some basic Lua (the language behind Codea) first, then the graphics part of Codea. I have some ebooks here that may help, written from my own learning experience.

https://www.dropbox.com/sh/mr2yzp07vffskxt/AACqVnmzpAKOkNDWENPmN4psa

Then I would start with very simple programs, like bouncing a ball around the screen, and playing with other people’s code, and work up from there.

Finally, learning to program, even a simple language like Codea, isn’t an easy ride. You have to be prepared to search widely for solutions when you get stuck, and spend time figuring things out. We would like to make it easier, but we are a very small group who only do this as a hobby. So while we are happy to help fix code problems, we don’t have the resources to produce ABC guides or provide personal tuition. I’m sorry, it’s just the way things are.