If we click and drag one of the rulers toward the center of the image, a movable dashed line appears in blue and black. This line is called a guide. In Figure 10-6, you see a vertical guide and a horizontal guide, which cross at coordinates (1000, 1000).
Guides have many useful options. Figure 10-7 shows the Image: View menu, which you use to access some of them. If the SNAP TO GUIDES box is checked, the mouse pointer “snaps up” to the nearest guide if it’s closer than the set threshold (threshold adjustments are covered in Chapter 22). Figure 10-8 shows how the guides can be used to ensure the upper-left corner of a cropped area is located at (1000,1000) in the original image.
Figure 10-8. Using the guides for precise cropping
Figure 10-9. The ...