Preview: Image Management

As mentioned previously Preview can open many image formats and make some very common operation such as cropping a picture or make the background transparent image.

So we go to open any image at your disposal and, going to look at the toolbar again, we see that the rectangle next to the button has an arrow that when clicked will display the following menu containing some tools:

The first three menu items allow you to select a rectangular area of ​​the image will be if you click the first item, if you click on the second item of choice and then the third item allows you to make a freehand selection. To crop the image content of the selection is enough to go in the application menu, click Tools and then click Crop or press cmd keys in sequence and k on the keyboard.

At the end of the procedure just explained we only output the image inside the selection and the remaining shares will be deleted. But if I wanted, through the selection, select and delete that element ELEMENTS keeping all the rest of the image? And 'possible to do this simply by inserting an additional step of selecting the item and the execution of the Crop. It 'must go to the preview menu bar, select Edit and then Invert Selection. In this way, the selection will be inverted and previously created now so if you run the comondo cuts will keep the whole image, except that portion identified by the selection.

Another very powerful tool that provides us with Preview Tool Lanyard is smart. This is very similar to the selection lasso, but has the advantage that after the selection made ​​by the user, automatically performs Preview a refinement of the selection that best fits the edge of the selected item. We show now an example of using this tool. Open any image you have available, select Smart Lasso tool, click and hold on the image you are looking to follow the edges, even in a non-specific, select the element you want (in the screenshot the goal is to isolate the string "Mr."):

Releasing the mouse button you will see that the selection will fit in the best way to the edges of the image as shown in the following screenshot:

This result is obviously not possible when using the Lasso Selection tool that does not make any adjustment to the image edges.

The last entry in the initial menu shown in the screenshot we analyze is Instant Alpha tool and is the tool that we use to make background transparent un'imagine. So we select this tool, we click on the background image and move the mouse, while pressing, until the whole part that we want to make transparent del'immagine turns orange. Releasing the mouse button get An effect of this type:

At this point we go to the preview menu, click on composition and then invert selection. We will see that the selection will undergo a reversal dashed and now just go to Tools and then click Crop to remove the background getting the following image:

If, as shown in the picture, we could not remove all the background image, simply repeat the process explained above background on the parts yet to be deleted.

In addition to basic image editing tools presented in this chapter, Preview implements a mode for images. To enable this feature, just select with the mouse you want to reproduce the images in the presentation, drag those images to the Preview icon in the dock and wait for the application opens. Once launched, you will see a photo displayed in the center window and the sidebar thumbnails of other photos. To enable the presentation will thus simply go to the Preview menu bar, select View and then click Show.

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