canvas drawing help (setpen,lineto,putpixel,moveto,erase)

[savvy]

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lineto(0,0);

a function used to draw lines in a canvas from one point to another... helpful in many ways including images.
heres how it works::

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setpen(255,200,250,0,1);

this turns the canvas into.. a canvas of art
255:red
200:green
250:blue
0:transparency
1:line thickness

moveto(0,0);
moves the starting point of your shape/line to this point.
(bare in mind the points are now relevant to the canvas, 0,0 is the top left corner of the canvas.)

lineto(20,20);
this will draw a line from point 0,0 to point 20,20 on the canvas.
the next lineto will draw a line from the above 20,20 to the new point.

for example: a box,

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setpen(255,0,0,0,1);
moveto(0,0);
lineto(0,10);
lineto(10,10);
lineto(10,0);

simple 10x10 pixel box.

can also make the canvas itself a box by replacing the x 10s with width and the y 10s with height.

throughout a canvas you can make the pen colour change, if you want to outline the canvas in blue then draw a box in red. just simply write
setpen with another colour value before your box.

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setpen(0,0,255,0,1);
moveto(0,0);
lineto(width,0);
lineto(width,height);
lineto(0,height);

setpen(255,0,0,0,1);
moveto(10,10);
lineto(10,20);
lineto(20,20);
lineto(20,10);


there is also erase(0,0,0,0);
this is used to remove any unwanted lines/pixels. put this at the top of a script. (below any variable declarations (int i = 0;))

then putpixel(0,0);
this places 1 pixel in the position indecated.

hope this was helpful its how many minimaps are made on GE and many games in general, experiment with it and enjoy.

savvy

[littlenatnatz101]

Love this tutorial!! It's awesome.
well done xxx

[SuperSonic]

Nice
(I'd give you a point but I just gave one to Hblade)

[savvy]

lol, cheers mate

[SuperSonic]

Never mind, you've got a point now^^

[Hblade]

Nice

[ITomi]

Interesting...
I tried to draw a rectangle with the mouse, but it always shows the previous draws on the screen. What is wrong? Here is the code of my canvas actor:

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int w,h;

setpen(0,0,255,0.0,1);
screen_to_actor(&xmouse, &ymouse);
w=x-xmouse;
h=y-ymouse;
moveto(0,0);
lineto(0,h);
lineto(w,h);
lineto(w,0);