Tài iệu Photoshop cs5 by Dayley part 89 docx

Instead of a bounding box with handles, the Warp transformation creates a 3x3 grid across your image.. Choose Edit ➪ Transform ➪ Warp to create the grid around your selection.. l Warp:

The Skew transformation allows you to move the corner handles independently of one another to pull or push the pixels in that corner closer to or away from the reference point This transforma-tion actually morphs the pixels in the area that is being pushed or pulled by merging them or dou-bling them so it looks as if the image is still contained in its entirety in the skewed shape

Skewing text is more constrained Rather than each corner being moved independently, the sides move together to create a sheering effect An example can be seen in Figure 19.4

To skew a selection, choose Edit ➪ Transform ➪ Skew A bounding box is created, and you can pull on the corners to transform them You also can type a degree of skew in the options bar This constrains your image to being skewed as a whole rather than one corner at a time (Keep an eye

on those numbers when you are dragging one corner; in order to skew just one corner at a time, not only the skew degree, but the relative position of the reference point changes.)

FIGURE 19.4

Pull on the corners to skew an object

Set skew

Distort

Distorting an image works much like taking a printed photograph and bending this way and that

to make it look different Distorting in Photoshop works better, of course, because you can make more dramatic distortions without creating any wrinkles The Distort option can make your selec-tion look angled, bubbled, or squished

Choose Edit ➪ Transform ➪ Distort to create a bounding box around your selection Use the han-dles to distort freely, as seen in Figure 19.5

Note

If you have just created a path, such as the shape that is being used in the distort example, you find that the

Edit menu contains the option to Transform Path, rather than Transform n

FIGURE 19.5

Using the Distort transformation can really change the look of your object

Perspective

The Perspective transformation widens either the top or the base (or both) of your image to correct perspectives that can be warped by fish-eye lenses or simply by the focal length of the image taken

The need for a perspective fix is most obvious in photos of tall buildings taken from the ground

Because of the perspective created by the lens, the buildings actually look as if they are leaning toward one another, as you can see in Figure 19.6 With a simple Perspective transformation, the tilt of the building is corrected and the subject of the image becomes the focal point Pulling on the side handles when using the Perspective transformation skews it

Note

As you change the perspective of an image, the center of it becomes fatter After you have restored the correct

perspective, you can scale your image to be taller, taking out the width distortion that the perspective fix

introduced n

Fixing the perspective can reduce or eliminate leaning objects in an image.

Warp

Warp is different from every other transformation I’ve shown you so far Instead of a bounding box with handles, the Warp transformation creates a 3x3 grid across your image This grid can be adjusted at each of its conjunction points to distort the image The area around the point used changes the most, with the surrounding areas being affected radiating out from the central point

Each corner of the grid also has two control point handles that control the curve of the grid and, therefore, the warp

Choose Edit ➪ Transform ➪ Warp to create the grid around your selection Warping is great for giving a three-dimensional look to photos or objects that are flat Figure 19.7 shows how an image

of a fish was changed to look as if the fish were swimming through three-dimensional space, rather than the two dimensions created by a flat screen

You can use any one of several preset warps by using the drop-down box in the options bar shown

in Figure 19.8

FIGURE 19.7

Adding a third-dimensional look to this fish just took a little tweaking with the Warp tool

FIGURE 19.8

Using any one of these options creates a preset warp

Free transform

With a few hotkeys memorized and a bit of ingenuity, you can perform any one of the above trans-formations with the Free Transform option The best thing about this option is that it already has a hotkey assigned to it, so rather than choosing Edit ➪ Free Transform, you can simply use Ctrl/Ô+T

to bring up a transformation bounding box You can use each of the following transformation tools

in this way:

l Scale: The bounding box is all set to scale your selection Just drag any of the handles like

sided arrow that indicates you can rotate Drag and rotate freely

l Skew: To skew your selection, hold down the Ctrl/Ô and Shift keys simultaneously while

dragging the handles

l Distort: You can distort by holding the Ctrl/Ô key while moving the handles This allows

you to distort freely without regard to the reference point To distort using the reference point, use the Alt/Option key

l Perspective: To change the perspective, hold the Shift+Ctrl or Ô+Alt or Option key while

dragging the handles

l Warp: You can warp a selection from any of the other transform tools by clicking the

Switch between Free Transform and Warp Modes button shown in Figure 19.9 This tog-gles between the standard bounding box and the grid you see when performing a Warp transformation

FIGURE 19.9

Click the Switch between Free Transform and Warp Modes button from any transformation options bar to

warp your selection

Switch between Free Transform and Warp Modes

Content-Aware Scale

The Content-Aware Scale allows you to make images larger or smaller without shrinking or distort-ing the subject of the image This is great for makdistort-ing photos smaller without actually croppdistort-ing out any content or making photos larger to expand a background to get a more dramatic effect or in order to add features to the image

Content-Aware Scale can work automatically by letting Photoshop guess what the main subject of the image is or by locking any pixels that are skin tones At best, these methods are hit-and-miss and leave you little control The best way to use the Content-Aware Scale is to create an alpha channel that protects the areas you want to stay constant

Figure 19.10 is a photo of Brad in front of an Indian palace Using the Content-Aware Scale, I can change the perspective of the palace in the background This is a great photo to use, because you can see how far you can push the hard lines in the image before they are broken up or warped

Keep an eye on the columns of the palace and the fence as you make changes

FIGURE 19.10

Can we scale the palace and leave Brad intact?

On the Web Site

You can download Figure 19-10 and use this photo to try the Content-Aware Scale Find it on this book’s

Web site n

I am going to show you the results of four different ways to use the Content-Aware Scale First, without any protection at all; second, protecting skin tones; third, protecting an alpha channel and skin tones; and last, protecting just the alpha channel For this example, I created two layers, one with the image and the second a transparent background that is larger than the image so I can scale larger

Try different methods of using the Content-Aware Scale by following these steps:

1 Create a selection around Brad

It doesn’t have to be extremely precise, but a good outline is best

2 In the Channels panel, click Save Selection as Channel to create an alpha channel

that protects Brad from being squished.

then return to the Layers panel.

4 Choose Edit ➪ Content-Aware Scale to create a bounding box around the image.

5 In the Options bar, make sure the Protect option is None and the Protect Skin Tones

button (the silhouette of the man) is not highlighted

6 Squeeze or stretch the image at will, keeping an eye on Brad and the straight lines

of the palace

You actually have quite a bit of latitude, especially side to side Eventually, as you squeeze the photo down, you lose Brad’s face Figure 19.11 is just smaller than I could make the picture and retain a realistic version of Brad The lines of the palace are just starting to warp as well This image is significantly smaller than the original, so the Content-Aware Scale worked very well

FIGURE 19.11

With no protection, the Content-Aware Scale provides quite a squeeze before collapsing Brad’s face

7 Click the Protect Skin Tones button.

This shows you a real-time change, as shown in Figure 19.12; now Brad’s face is less dis-torted and his arms look right, but the rest of his body is hopelessly puckered and out of shape, along with most of the surrounding palace This isn’t the right option for this photo!

FIGURE 19.12

Protecting the skin tones does nothing to protect the white of Brad’s shirt!

8 Use the Protect drop-down menu to choose Alpha 1.

Now the pixels protected by the alpha channel should revert to their original state In Figure 19.13, Brad looks great, but the palace is sadly out of shape Turns out that Photoshop is interpreting the putty-colors of the palace as skin tones Maybe protecting the skin tones is not the best option

Even though Brad looks great, the palace is puckered and misaligned.

9 Click the Protect Skin Tones button to turn it off

Figure 19.14 shows the best result yet Brad is protected, and the palace has very few lines that are out of shape By stretching this image just a little bit, I get a satisfactory result

FIGURE 19.14

Protecting the alpha channel and not the skin tones is the best option

Using the all-new Puppet Warp

The Puppet Warp tool is new in CS5, and it gives you lots of control when it comes to changing the way a previously flat, two-dimensional image looks It works by placing a mesh over the selected area in your image, giving you the ability to warp and move individual areas of the image, almost as if it were a piece of fabric Using pins to hold areas in place and others to move your image, you can choose which areas to move, how they’ll move, and how far

It’s fun to try on an image with several independent areas Figure 19.15 shows a spider on its own layer Using Puppet Warp, you can move each of her legs independently