# A quick question about the 1st chapter of Processing

Can anybody also please help me with my following query ? In the page 6 of the Processing textbook, a line has been drawn ( as can be seen in the attached picture Figure 1-6) on a graph paper and I can’t understand how the writer got the line numbers ( 1,3 , 8, 3 ) from Point A to Point B ? Neither do I understand how did the writer got those numbers in Figure 1-7 of the page 6.

It’s been a while I studied grap and as result can’t remember anything about graph !!!

Any help will be greatly appreciated. Thanks heaps

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Yeah pretty much the columns are numbered in x direction and the rows/lines are numbered in y direction.

Similar to a Chess board you can therefore define a point by its column and row. Where those two meet is your point.

LINE

Two points x,y make a line

x1,y1 TO x2,y2

For a rectangle we specify the point upper left corner again as `column number , row number`.

The next two parameters specify `width and height` of the rectangle in pixels

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Hello,

Check out the resources (tutorials, references. examples) available here:
https://processing.org/

There is a good tutorial here:
Coordinate System and Shapes \ Processing.org

There is also the Coding Train on YouTube… there may be a good tutorial there.

`:)`

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You are a champ, may peace be upon you

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Hello,

This is an example to try:

``````void setup()
{
size(300, 300);
}

void draw()
{
background(0);
int x = mouseX;
int y = mouseY;

//Text to console
println(x, y);

//Text on screen
textSize(16);
textAlign(CENTER);
text(str(x) + ", " + str(y), x, y);
}
``````

As you move the mouse around it displays the (x,y) co-ordinate on the screen and on the console.

`:)`

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Thanks champ. I really appreciate your benevolence. Thanks again

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