Adobe Photoshop CS5 for Photographers - Martin Evening [28]
When you are viewing an image in close-up, you can select the hand tool from the Tools panel ( ) and drag to scroll the image on the screen, plus you can also hold down the Spacebar at any time to temporarily access the hand tool (except when the type tool is selected). The hand and zoom tools also have another navigational function. You can double-click the hand tool icon in the tools panel to make an image fit to screen and double-click the zoom tool icon to magnify an image to 100%. There are also further zoom control options in the zoom tool Options bar (Figure 1.73).
Figure 1.73 You can use the Zoom tool Options bar buttons to adjust the zoom view. If OpenGL is enabled ‘Scrubby Zoom’ will be checked. This overrides the marquee zoom behavior – dragging to the right zooms in and dragging to the left zooms out. Personally, I prefer to keep this option deselected.
The eyedropper tool can be used to measure pixel values directly from a Photoshop document and these values are displayed in the Info panel shown in Figure 1.71. Photoshop CS5 now also features a new Heads Up Display, which I have described in Figure 1.72. The color sampler tool can be used to place up to four color samplers in an image to provide persistent readouts of the pixel values, which is useful for those times when you need to closely monitor the pixel values as you make image adjustments.
Figure 1.71 The Info panel showing an eyedropper color reading, a measurement readout plus two color sampler readouts below.
Figure 1.72 This shows the Open GL eyedropper wheel. The outer gray circle is included to help you judge the inner circle colors more effectively. The top half shows the current selected color and the bottom half, the previous selected color. The sample ring display can be disabled in the eyedropper options.
The ruler tool can be used to measure distance and angles in an image and, again, this data is displayed in the Info panel. But note that the count tool is only available in the extended version and is perhaps more useful to those working in areas like medical research where, for example, you can use the count tool to count the number of cells in a microscope image.
Flick panning
With OpenGL enabled in the Photoshop Performance preferences, you can also check the ‘Enable Flick Panning’ option in the General preferences (see page 101). When this option is activated, Photoshop will respond to a flick of the mouse pan gesture by continuing to scroll the image in the direction you first scrolled, taking into account the acceleration of the flick movement. When you have located the area of interest just click again with the mouse to stop the image from scrolling any further.
Bird's-eye view
Another OpenGL option is the Bird's-eye view feature. If you are viewing an image in a close-up view and hold down the key as you click with the mouse and hold, the image view swiftly zooms out to fit to the screen and at the same time shows an outline of the close-up view screen area (a bit like the way the Navigator panel view works). With the key and mouse key still held down, you can click and drag to reposition the close-up view outline, release the mouse and the close-up view will re-center to the newly selected area in the image (see Figure 1.74).
Figure 1.74 If a window document is in OpenGL mode and in a close-up view, you can hold down the key and click with the mouse to access a bird's-eye view of the whole image. You can then drag the rectangle outline shown here to scroll the image and release to return to a close-up of the image centered around this new view.
More zoom keyboard shortcuts
Traditionally, the shortcut is used to zoom to a 100% pixels view and the shortcut is used to zoom out to a fit to view zoom view. Photoshop now also uses the shortcut to zoom to 100%. This was first implemented in CS4 in order to unify the window document zoom controls across all of the Creative Suite applications. As a consequence of this, the channel selection shortcuts have been shifted