Add line tool and undo tools

core/src/io/anuke/mindustry/ui/GridImage.java

@@ -0,0 +1,37 @@
+package io.anuke.mindustry.ui;
+
+import com.badlogic.gdx.graphics.g2d.Batch;
+import com.badlogic.gdx.graphics.g2d.TextureRegion;
+
+import io.anuke.ucore.core.Draw;
+import io.anuke.ucore.scene.Element;
+
+public class GridImage extends Element{
+	private int imageWidth, imageHeight;
+	
+	public GridImage(int w, int h){
+		this.imageWidth = w;
+		this.imageHeight = h;
+	}
+
+	public void draw(Batch batch, float alpha){
+		TextureRegion blank = Draw.region("white");
+		
+		float xspace = (getWidth() / imageWidth);
+		float yspace = (getHeight() / imageHeight);
+		float s = 1f;
+		
+		for(int x = 0; x <= imageWidth; x ++){
+			batch.draw(blank, (int)(getX() + xspace * x - s), getY() - s, 2, getHeight()+ (x == imageWidth ? 1: 0));
+		}
+		
+		for(int y = 0; y <= imageHeight; y ++){
+			batch.draw(blank, getX() - s, (int)(getY() + y * yspace - s), getWidth(), 2);
+		}
+	}
+	
+	public void setImageSize(int w, int h){
+		this.imageWidth = w;
+		this.imageHeight = h;
+	}
+}