Rotating text from a left anchor

Programming Questions

cjheadlea..

Rotating text from a left anchor

in Programming Questions • 10 months ago

Hi All,

I'm drawing a bar graph where my labels are quite long along the X axis. To sort this out I want to rotate the labels by 20 degrees, pointing down left to right.

I started by getting the X and Y in the right position so the text was in the right position unrotated however when I added the rotate command the text ended up in the wrong position (significantly). The whole text moved off to the left and down.

Is there anyway to lock the point of rotation to the left of the text? I tried using text align but that had no effect.

Cheers.

Replies(6)

timpulver

Re: Rotating text from a left anchor

10 months ago

Just tried it and the text is where it should be (rotation point is bottom left point of the text).

int x = 30;
int y = 30;
void draw(){
background(0);
fill(255, 0, 0);
noStroke();
ellipse(x, y, 3, 3);
fill(255);
stroke(255);
pushMatrix();
translate(x, y);
rotate(HALF_PI);
text("test", 0, 0);
popMatrix();
}

cjheadlea..

Re: Rotating text from a left anchor

10 months ago

Hi, I'm still having the same issue..

This is the code without the rotation

if (labels1 == true)
{
pushMatrix();
textSize(10);
fill(000);
text("hello", xax, yax + 10 + r3);
popMatrix();
}

This gives me the following output where the left letter is where I want it to be (at the bottom left of my little bar graphs)

But when I try to rotate it using this code

if (labels1 == true)
{
pushMatrix();
rotate(0.2);
textSize(10);
fill(000);
text("hello", xax, yax + 10 + r3);
popMatrix();
}

I get this output

What I want is the first letter of the text to be the ancor and be connected to the bottom on my graph. however each item is getting shunted off and too the right.

Can anyone advise what I need to do to fix this?

timpulver

Re: Rotating text from a left anchor

10 months ago

Look at my code. You need to translate to the point where the text should be drawn to before the rotation.

If you don't call translate before, everything will be rotated around (0, 0).

You then have to replace text("text", x, y) with text("text", 0, 0).

cjheadlea..

Re: Re: Rotating text from a left anchor

10 months ago

Hi Tim, Thanks for your help... Im not sure entirely what you mean. I just looked at the translate page too and didnt quite get it.

In my code the bargraphs are drawn using a for loop which increments the X position and the y position

I call these vairables xax and yax. However if I use these vairables in translate

translate(xax,yax); the text ends up almost off the page.

the code I use is here

if (labels1 == true)
{
pushMatrix();
translate(xax, yax);
rotate(0.2);
textSize(10);
fill(000);
text(uni, xax, yax);
popMatrix();
}

quarks

Re: Rotating text from a left anchor

10 months ago

Before you rotate the axis you must tanslate to the pivot point try this (I haven't tested it

if (labels1 == true)
{
pushMatrix();
translate( xax, yax + 10 + r3); // translate to text pivot point
rotate(0.2); // rotate axis
textSize(10);
fill(000);
text("hello", 0, 0);// already at text start point so use 0,0
popMatrix();
}

cjheadlea..

Re: Re: Rotating text from a left anchor

10 months ago

Your my hero!

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