Note that the wand tool may not be able to reliably trace a one pixel wide line unless it is first thresholded. Line Selection Tools Use these tools to create line selections. Double click on any line tool to specify the line width. Straight Line Use this tool to create straight line selections. Draw Arrow will draw an arrow based on a straight line selection.
Segmented Line Create a segmented line selection by repeatedly clicking with the mouse.
Each click will define a new line segment. Double-click when finished. Freehand Line Select this tool and drag with the mouse to create a freehand line selection. Mark and Count Tool Use this tool to count objects. Clicking on a point in the image records its location and intensity and draws a mark in the current foreground color.