LibGDX - Gradient rectangle using 2x2 texture (or similar way?) - opengl

Question

CMIIW: I heard libgdx's ShapeRenderer is slow and it is better to use Batch.
I tried using Pixmap to produce 2x2 texture and rely on the linear blending:
public void rect(Batch batch, float x, float y, float w, float h, float rot, Color c00, Color c01, Color c10, Color c11){
Pixmap pm = new Pixmap(2, 2, Format.RGBA4444);
pm.drawPixel(0, 0, Color.rgba8888(c00));
pm.drawPixel(0, 1, Color.rgba8888(c01));
pm.drawPixel(1, 0, Color.rgba8888(c10));
pm.drawPixel(1, 1, Color.rgba8888(c11));
Texture tx = new Texture(pm);
tx.setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear);
batch.end();
batch.begin();
batch.draw(new TextureRegion(tx), x, y, w/2f, h/2f, w, h, 1f, 1f, rot, true);
batch.end();
batch.begin();
tx.dispose();
pm.dispose();
}
And it produces this:
It is not the effect I would want.
If I could throw half pixel from each side of the texture then I think it would be good.
I thought in order to do that I have to change the TextureRegion to this:
new TextureRegion(tx, 0.5f, 0.5f, 1f, 1f)
but this produces:
What is happening there?
Or is there better way to efficiently draw gradient rectangle?
EDIT:
Ouch! Thanks TenFour04 - I tried with
new TextureRegion(tx, 0.25f, 0.25f, 0.75f, 0.75f) but got this instead:
weird, I got exactly what I want with
new TextureRegion(tx, 0.13f, 0.13f, 0.87f, 0.87f):
looks like some rounding problem? 0.126f would still give me that (seemingly) but 0.125f would give me something much closer to the very first image in the post.
#Pinkie Swirl: hmm right, I wanted a method to draw gradient rectangles because I don't want to make textures, but in the end I do.. actually I can avoid making those 2x2 textures on the fly.
#minos