Teach Yourself
CorelDRAW 8 in 24 Hours
In Hour 1 of this book, you learned the difference between CorelDRAW's vector-based graphic images and bitmap images. Vector-based images consist of curves and nodes, which are stored on file as mathematical formulas, generated as you draw. Because of this, CorelDRAW gives you unmatched power to draw complex and smooth curves.
Furthermore, because objects in CorelDRAW are saved as formulas, these images can be reproduced at any size, from a postage stamp to a billboard. You will start to notice the difference between bitmap- and vector-based graphics when you attempt to edit them. Bitmaps cannot have outlines and fills defined with the same detail that vector-based images can. When vector-based images are enlarged, they maintain the same outline and fill characteristics. In Figure 11.1, the vector-based dinosaur has the same outline width even when enlarged five times, whereas its bitmap-based cousin does not maintain the same outline characteristics.
The vector-based dinosaur on top keeps its outline width even when enlarged five times; the outline on the bitmap dinosaur on the bottom gets thicker when the object is enlarged.
The advantages to using bitmap images include:
For these reasons, it is important that you become "bilingual" as far as graphic image formats and that you learn to work with bitmap images as well as vector images. In this lesson, you learn to incorporate bitmap images in your CorelDRAW illustrations.
When you start working with Corel PHOTO-PAINT 8, in Hour 20, "PHOTO-PAINT Basics," you'll be introduced to bitmap images in detail. PHOTO-PAINT is exclusively a bitmap image editing program. But here's the "short course" on what bitmaps images are and how they work.
Simply put, bitmaps are images that store a location and description of pixels. Pixels are nothing but dots. So rather than defining images in terms of curves and lines, bitmap images are defined as dots.
Bitmap properties are defined mainly by the resolution of the image and the number of colors that compose the image. These two properties determine the quality of the image and the size of the file. As you might guess, higher-quality images take up more disk space.
Frequently used bitmap resolutions include 300 dots per inch (which is what older laser printers use to reproduce images), 600dpi (which is what newer laser printers support), and 72dpi (which is what most computer screens use). If, for example, you are creating an image for a web site, don't assign a resolution higher than 72dpi because the final output (a computer screen) will not support the additional pixels. When you work with bitmap images in CorelDRAW, you assign resolutions to them.
Bitmap images can also have different numbers of colors. Those include black and white images, 8-bit grayscale (256 shades of gray), and 8-bit paletted (256 colors). Other color modes exist as well, but these are sufficient to use with most bitmap images that you will work with in CorelDRAW. When you explore PHOTO-PAINT 8, you'll learn to use bitmap color modes that support even larger numbers of colors.
CorelDRAW is not really a full-features bitmap editor. PHOTO-PAINT is. And with every copy of CorelDRAW 8, you get PHOTO-PAINT 8 free. So what's the point of editing bitmaps in CorelDRAW 8? If you work exclusively with bitmap images, you should work in Photo-Paint instead of CorelDRAW. But if you combine both vector and bitmap images, CorelDRAW supports this much better than PHOTO-PAINT or any bitmap editor.
At this point, you might be asking yourself, "Can't we all just get along? Why can't somebody come up with a program that will edit both bitmap- and vector-based graphics?" Well, somebody has, and you're using the program. CorelDRAW 8 includes a Bitmap menu that lets you create, edit, and save bitmap images in CorelDRAW. So, in effect, you can work in a mixed environment.
The one thing that you cannot do is transform bitmap images to vector-based images. Programs exist that attempt to trace the lines in bitmap images and convert them into vector-based curves, but these programs are basically trying to guess at which dots should be converted to which lines, and the results are usually not satisfactory.
Several ways to get bitmap images in CorelDRAW include:
In this section of Hour 11, you learn to obtain bitmap images in CorelDRAW using all four of these techniques.
Scanning has become much more accessible over the last year or two. The price of scanners has been plummeting, and quality flatbed scanners can be bought for not much more than a hundred dollars if you watch for rebates and sales.
Scanning has also gotten easier to do. CorelDRAW 8 comes with CorelSCAN, a program that walks you through the process of scanning photos or other images into CorelDRAW.
After connecting your scanner ( which is beyond the scope of this book, but most scanners come with easy-to-follow instructions), CorelSCAN helps you decide what bitmap format you want to assign to your imported image.
Just A Minute: Your scanner dialog box prompts you to tell it what type of bitmap image you want to create from your scanned image. Ignore these settings for now, as CorelSCAN soon takes over to help you make these decisions.
CorelSCAN 8 helps you figure out which of the many types of bitmap formats is appropriate for your image.
The paletted (256 color) color mode is perfect for creating bitmap images that will be used in a web site.
Because I'm designing an image that I expect to be viewed on a web site by Internet Explorer, I'm choosing that color palette.
CorelSCAN knows that my web image should have 72 dots per inch.
These filter dialog boxes also have sliders that enable you to determine how much of the various effect(s) you want to apply to your scanned image.
Each of the filter dialog boxes has three buttons underneath the preview area: the Navigator, Preview, and Reset buttons. These dialog boxes have check boxes that enable you to apply the effect to your scanned image.
You can control what part of your image is visible in the Preview window. When you click on the Navigator button, a thumbnail image appears, and you can select the portion of your image that you want to appear in the Preview window. You can also move the section of your image that is visible by dragging directly on the left side of the Preview window. In Figure 11.6, I am dragging the image using the grabber hand that appears when I move my cursor over the left Preview window.
If you don't like the effect that you applied, click on the Reset button (it looks like an Undo button).
CorelSCAN comes with filters that are controlled and applied with sliders.
Another way to place a bitmap image in the CorelDRAW Drawing window is to import an exiting image. This is a cinch. Simply select File | Import from the menu bar, and use the Look In drop-down list to navigate to the folder on your system in which your graphic files are stored. Or if you are opening one of the thousands of bitmap clip art images that come with CorelDRAW from your CD-ROM, navigate to your CD drive.
If you click on the Preview check box in the Import dialog box, you can see a thumbnail of your image before you elect to import it. In Figure 11.7, I've found the graphic image I want, and I'm looking at it in the Preview window.
The Preview check box turns the Import dialog box into a graphic index of your saved images.
When you find your image, double-click on it to import it into your open CorelDRAW drawing.
The easiest way to bring bitmap images into CorelDRAW is to copy and paste them. Any image that you can see on your computer screen can be copied and pasted into CorelDRAW as a bitmap object. That includes images that you see on the World Wide Web (provided of course that you have permission to copy them).
Just A Minute: If your program does not support this method of copying an image using the right-click shortcut menu, you can select the image and choose Edit | Copy from your menu bar. Or if neither of those options are available, click on the image and press Ctrl+C on the keyboard.
I checked to make sure it was okay to copy images from this web site before pulling a graphic into CorelDRAW 8.
Most of the time when you work with bitmap objects within CorelDRAW it will be because you brought a bitmap image from somewhere else into CorelDRAW. However, sometimes you'll want to convert a vector image into a bitmap so that you can apply effects only available in bitmap images. To learn how to do that, read on.
You can create bitmap images from CorelDRAW by first designing a drawing. To do that, just create a drawing in CorelDRAW. Select the objects that you want to convert into a single bitmap image, and then choose Bitmaps | Convert to Bitmaps from the menu bar.
The Convert to Bitmap dialog box offers you options similar to those you chose from when you scanned an image. The Color drop-down menu offers different color modes. Paletted is best for images that will be placed on web sites. One color is best for black-and-white drawings. RGB or CMYK color is best for images that will appear on a high-resolution monitor or printed using a color printing process.
The Dithered check box enables a feature (dithering) that compensates for colors that are not on your color palette by mixing colored dots. The Transparent Background check box can eliminate a colored background from your image. The Resolution drop-down list enables you to choose how many dots per inch (dpi) you want to assign to your image. More dots make a higher quality image but take more disk space. The projected file size is shown on the bottom of the dialog box and changes as you select color and resolution settings.
Antialiasing is discussed in some detail in the hours in this book devoted to PHOTO-PAINT. The short explanation is that it eliminates jagged edges in bitmap objects, but the downside is that it makes them blurrier. The Convert to Bitmap dialog box gives you three Antialiasing options: None, Normal, or (the max) Super-sampling.
After you define settings for your selected object(s), click on OK.
After you create a bitmap image in CorelDRAW 8, you can apply some useful effects that are not available for vector-based objects.
Those effects include using a color mask to strip any unwanted color out of an image, assigning transparency to bitmap images so that they appear to have no background when displayed on web sites, and applying a fun range of distortion effects to your image.
Other effects include transformations with names such as Solarize, Impressionist, Psychedelic, Glass Block, and Vignette.
You can use bitmap color masks to eliminate any color from any bitmap image. This is especially useful with scanned or imported photos. Color masking can be, in effect, a recoloring tool. Too much red or blue in a photo? You can correct that with color masking.
You can also use color masking to transform the fills of any bitmap images.
Use the color selector to create a perfect match for a color you want to remove from a bitmap image.
Moving your eyedropper-cursor even one pixel can change the selected color.
The Bitmap Color Mask rollup is basically a "decolorizer."
Transparency is like color masking, but a bit simpler. When you assign transparency to a bitmap image, you strip away a single background color.
You can use the Convert to Bitmap dialog box to transform existing bitmap images. If you copy or import an image with a background that you want to remove, select it, choose Bitmap | Convert to Bitmap from the menu bar, and use the Transparent Background check box to strip the background from the image.
CorelDRAW's Bitmap menu includes a number of fun distortion effects that you can apply to bitmaps. These effects are culled from the arsenal that you will learn to use in the hours on Corel PHOTO-PAINT. You'll investigate these effects more in those hours (20-22), but you can try 3D effects now.
Not all Bitmap effects can be applied to every bitmap. The available effects depend on the color mode and type of the bitmap image.
When you select a bitmap image and choose an effect from the Bitmap menu, you can see the changes you are applying in two different ways. In the effect dialog box, shown in Figure 11.12, you can click on the Preview button to display changes you make with the sliders before they are applied to the image in the Drawing window.
You can preview bitmap effects in a dialog box.
The three buttons in the effect dialog box enable you to add your effect to the display in the Preview window, to display the effects in the Drawing window, or to automatically transform the image in the Preview window as you experiment with changes in effect settings.
If you choose the left-most button in the Preview dialog box, your effects dialog box no longer includes a Preview window, and effects appear on the screen, as shown in Figure 11.13.
When you toggle to the effect dialog box without a Preview screen, the button on the left toggles back to the Preview dialog box, and the button on the right displays the effect you are defining in the Drawing area.
When you have defined and previewed a bitmap effect, click on OK in the dialog box to apply that effect to the selected bitmap object.
You can also preview bitmap effects in the Drawing area.
You have many reasons to work with objects as bitmap images. You might want to import images in bitmap file formats. And many effects and distortion tools are available for bitmap images and not available for vector-based objects.
You can edit bitmap images in CorelDRAW, but many of the editing techniques you've learned so far do not apply to bitmaps. You cannot edit nodes or curves in bitmap images. But you can apply a sample selection of bitmap effects to these images.
In this workshop, you create a fun clock or compass by combining bitmap objects with vector objects and applying bitmap effects to the bitmaps. Feel free to skip steps that seem a bit over your level. You can still have fun applying bitmap effects even if you skip steps 2, 3, 4, or 5.
Converting the clock symbol to a bitmap enables you to assign bitmap effects to it.
You can convert more than one selected object to a single bitmap.
Nice work! Even if you didn't exactly follow my steps, you experimented with combining bitmap and vector objects.
© Copyright, Macmillan Computer Publishing. All rights reserved.
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