Graphics Basics. Outline

Transcription

1 Graphics Basics There are many ways to fiddle with graphics. This document presents a couple of ways to manipulate graphics and incorporate them into reports and presentations. It is not meant to be all encompassing. Also, the only way to really learn this stuff is to use it. Usually, anything you want to do to a document in an Office application can be done you just have to figure out how. Using the "Help" menu may be beneficial, but experimenting works too. Taking the time to right click and left click on images and reading through the various options and properties will probably be more beneficial than just reading through this document. Outline I Definitions 2 II Manipulatng Still Images 6 III Manipulating Digital Video 9 IV Incorporating Into Reports 10 Author: Len Cabrera, May 2001, Updated Dec of 13

2 I. Definitions. There are two basics areas in the digital imaging world: stills and video. Each has it's own language and equipment. The following should be enough to let you get by: Stills - examples include digital cameras, scanned pictures, and images created by computer software (Photoshop, Microsoft Imager, Corel, etc.) Color - goes hand-in-hand with resolution in determining how good the image looks. There are two ways that color has an impact. First, is the color saved in the file. The second is the color setting on the computer itself. If the image is set for millions of colors, but the display only supports 16, the image will only display 16 (i.e., it'll look bad). Typical color settings include monochrome, 16 color, 256 color, high color (16-bit), true color (24- or 32-bit). Monochrome is literally black and white (or some other color) where each pixel is one off (black) or on (white). That's not the same as a gray-scale which uses various combinations of black and white for each pixel (i.e., various shades of gray). For the lower color settings, a computer keeps a palette of colors in memory. If you tried to look at two 256-color images that have different palettes at the same time on the 256-color display, the second image will revert to the pallet of the first and may not look right. Memory and file sizes restrict the number of colors available. If possible, it's always best to save files in 24-bit (true) color. Format - the method used to save the image. There are tradeoffs in how an image is saved, the biggest being how large the file is versus how much resolution there is. Many of the formats have several options based on color, transparency, and compression. The basic types are files are:.bmp - "Windows Bitmap"; the typical format displayed on your screen. A bitmap contains all the original detail in the image for each pixel. They tend to be large files and do not handle resizing very well (especially making them bigger)..cgm - "Computer Graphics Metafile"; this is an ideal format for high resolution graphic objects that may be resized in future applications. Rather than saving individual pixels in an image, a CGM saves the actual drawing objects that make up the image (lines, circles, etc.). That allows the CGM image to be resized and gives it a generally smaller file size. Unfortunately, only higher end imaging software like CorelDraw allow saving in this format. Also, special graphics filters need to be installed in Word to use them. The filter comes with Word, but is rarely installed by system administrators who don't know about it..gif - "Graphics Interchange Format"; this is a common compression format. It is basically a bitmap (i.e., stores information on individual pixels), but it tends to blur because of the compression. Usually GIFs are limited to 256 colors, but they can handle transparencies. GIFs can also handle some limited animation if you use the proper software. The animation is limited to a series of GIF images displayed in sequence with a specified delay..jpg - "JPEG File Interchange Format"; similar to GIFs since it's basically a compressed bitmap. Unlike GIFs, JPEGs can handle more than 256 colors, but they cannot handle transparencies..tif - "Tag Image File Format"; another uncompressed bitmap. This is the default format for high resolution images in many scanning devices and cameras..pdf - "Portable Document Format"; although not technically an image format, Acrobat is used to lock documents for viewing. Word and other word processors attempt to have WYSIWYG (what you see is what you get) displays, but they are dependent on the printer driver selected. They also allow people to edit (for Author: Len Cabrera, May 2001, Updated Dec of 13

3 better or worse) the document. Adobe Acrobat can take a Word document and essentially makes it a series of images (one per page) that can be viewed independent of the computer platform, operating system, or printer driver. These files cannot be edited by the reader. Others - other software packages generate their own proprietary formats (Corel, Image Composer, PhotoShop, etc.). You can usually select "Save As " in any application and get one of the formats listed above (except.pdf). Resolution - tells how much detail is contained in the image, usually in pixels (dots). If the image is displayed on a computer screen at 100%, the resolution will also determine the size because it will translate the image to individual pixels on the screen. You can still shrink the picture to the size you want and maintain the high level of resolution. Resolution is determined at the time the image is created (by the camera, the scanner, or the software settings). Resolution is usually listed as two numbers: horizontal and vertical. Typical resolutions are: Horiz. Vert You'll rarely have pictures over 320x240 in a report. That means 640x480 or 800x600 (usually "medium" level) resolution is plenty for still shots. Higher resolutions may sometimes be required if you want a larger picture. An good 8x10 print, for example, generally requires a resolution above 1600x1200. Size - closely related to resolution for unedited images. If you're putting an image in Word or some other document editor, you may want to change the size of the picture to get the proper layout. Usually, the size can be set as a percentage of the original, in inches, or in pixels. To change the size in Word, select the picture (single left click on the image), then right click and select "Format Picture " Select the "Size" tab and enter the size you want. The windows will probably default to inches (set in the "General Options" tab of the "Options " item in the "Tools" menu). There are also selections for locking the aspect ratio (i.e., same ratio between vertical and horizontal size) and sizing relative to the original image (if using percentages). Note that resizing an image does not change the resolution, although making an image too big can make it blur if the resolution is not high enough. Transparency - some graphic formats allow a transparent color. That means that when the image floats above other objects or text, you can see the background objects/text through the transparency. The usual application for this feature is unit patches in PowerPoint. Video - examples include analog video cameras (VHS and 8mm tapes), digital video cameras, and computer software (e.g., QuickTime, Adobe Premiere, Macromedia Director). Author: Len Cabrera, May 2001, Updated Dec of 13

4 Frame Rate - tells how many frames (images) are displayed each second. Like most options in the graphics world, there is a trade off between quality and file size. Higher frame rates require much larger files for the same length video. High quality videos typically have 30 frames per second (fps). "Internet quality" videos may have as little as 10 fps which makes files sizes much smaller, but they tend to have choppy playback. For linking to reports, 15 fps is usually good enough Format - the method used to save the video. There are hardware formats and software formats. Just like with the stills, there are tradeoffs in how an image is saved with resolution and frame rate being the biggest factors. Many of the software formats have several options, especially when looking at compression, but be wary of using nonstandard (or even new standard) compression formats because most people will not be able to view the video. New "modular" media players (e.g., Microsoft Media Player 6.4 or later) keep individual decoding files in add-ins called "CODECs." If you try to play an unsupported video format on these players, they'll try to access the Microsoft home page to download the proper CODEC. (Unfortunately, the Hurlburt network does not allow the CODEC to be downloaded.) The basic types of format are: Hardware: 8mm - tapes from newer analog camcorders. The cartridges are roughly half the size of VHS with the tape being 8mm thick (hence the name). Beta - the original video cartridge tape system by Sony. The tapes are slightly larger than VHS and tend to have slightly better resolution. They are still used by video professionals (news rooms, etc.). CD - compact disc was a major step away from tapes. Unlike the magnetic media, CDs are based on optical recognition so they do not wear out (although dust and scratches can still ruin your information). There are several types of CDs used to store digital video: CD-ROM (read only memory; usually from manufacturers); CD-R (recordable; written to only once), and CD-RW (re-writable; written to multiple times). When burning (writing) a CD, a computer can record all the information at once or can use multiple sessions. Either way, the information cannot be read until the particular session is closed. Most CD-ROM drives cannot read the disc at all until the disc itself is closed (i.e., no more data can be written). Older systems may not be able to read CD-Rs and CD-RWs at all. The newer ones come with "multi-read" CD-ROM drives which can. Unfortunately, Windows NT 4.0 does not handle CD-Rs and CD-RWs that have been recorded with multiple sessions. DV - "Digital Video"; no real standard format exists in the realm of digital video. There are various types of tape cartridges that carry the DV logo. The two most prevalent are roughly the size of standard 8 and 4 mm analog tapes, the latter is referred to as "Mini-DV." DVD - "Digital Video/Versatile Disc"; the next generation CD. DVDs also work on optical recognition rather than magnetic media. The discs use a different format which store much more information. They can also record two layers per side for a total of 19 GB (vs MB on a CD-R). The standard DVD format (how you buy movies) includes MPEG2 compression for both audio and video. There are also DVD-RAM drives which are not exactly the same as DVD. (The discs in the DVD-RAM drive comes in a large cartridge and are not compatible with DVD- ROM drives). Hi-8 - basically SVHS for 8mm tapes. Author: Len Cabrera, May 2001, Updated Dec of 13

5 SVHS - "Super VHS"; uses the same physical cartridge and tape size as a VHS tape, but has nearly double the resolution. An SVHS player can read VHS tapes, but not vice-versa. VHS - "Video Home System"; tapes in your typical VCR and older camcorders. These have the advantage of having wide-spread players, but the picture quality is not the greatest. Software:.AVI - the highest quality video format available. Unfortunately, this format is also limited by large files and fixed size. The files are saved for a given resolution (i.e., pixels) so making them bigger or trying to play them full screen does not work very well. On the plus side, any version of Windows can play an AVI file. Note: Some digital cameras generate movies as.avi files, but they use special compression that cannot be read by Windows Media Player (not yet anyway). They require QuickTime 5.0 or later (available free from - "Moving Picture Export Group"; standard video compression format. There are actually a series of video and audio compression formats using the MPEG name. The most common would be the MPEG Audio Layer 3 (MP3) format made famous by Napster. Commercial DVDs use MPEG2 for both audio and video compression. Typical media players can usually handle MPEG 1 and 2, but later versions require new decoders from the software manufacturer (i.e., Microsoft).MOV - "QuickTime Movie"; digital video format by Apple. This technique compresses the files by just updating areas that change rather than saving a new image for each frame. Older QuickTime movies can be played on most media players, but the newest format generally can only be played with a QuickTime player. The player itself is freeware from Apple, but each successive version gets bigger and bigger. The latest version (5.01) requires Internet connectivity to finish download and may not be possible with the Hurlburt network. Resolution - tells how much detail is contained in each frame (just like resolution for stills). Resolution is determined at the time the image is created (by the camera or software settings). Although it can be changed during playback, altering the resolution essentially results in combining or stretching pixels and generally doesn't look as good as the original resolution. Higher resolutions gobble up memory much more than in still images and the longer the video, the greater the impact of increasing resolution. Video resolution listed as two numbers (horizontal and vertical) just like for still images. Just like with still images, 320x240 is usually a good trade-off between file size and resolution. This will result in about 3-4 MB for each 10 seconds of video, depending on the compression. Author: Len Cabrera, May 2001, Updated Dec of 13

6 II. Manipulating Still Images. Any computer with Microsoft Office has the necessary software to edit sill images: Microsoft Paint and Microsoft Photo Editor. This section will focus on these tools. There are always better, more sophisticated ways of editing stills which may be required for some images, but they require specialized software such as Microsoft Image Composer or CorelDraw. MS Paint - used for editing BMP images. The actual software is not very powerful but has one huge advantage: it comes standard with any version of Windows. You can use it to open BMP images or you can paste other image formats and edit them as bitmaps. Note that the compression used by other image formats may make it difficult to work with them as bitmaps. For example, if there is a section of blue that needs to be changed to red, the flood fill feature may not work because there will be many shades of blue (especially near other colors or lines). See the "Set Transparent Color" section under MS Photo Editor to learn how to solve this problem. Here are some of the basic tools available in MS Paint: Color Palette Erase The left side of the color palette (big area) shows what the selected foreground (black) and background (white) colors are. The foreground color is set by left clicking on one of the smaller color squares. The background color is set by right clicking. The significance of the background color comes into play when erasing or moving parts of the image. Double clicking on the individual colors on the right brings up a window to edit the color. A new one can be selected from a list of choices or customized from a more detailed menu. Note: If trying to match a specific color already in the image, see "Pick Color" below. Using this tool will cover everything under the curser with the background color while you hold the left mouse button. If you hold the right mouse button, this tool will replace the selected foreground color with the selected background color. Flood Fill This tool will use the selected foreground color to completely replace the color under the cursor. The paint bucket illustrates how the tool works. Picture pouring pain on the current color and it spreads out in all directions until it hits a different color. Pick Color The dropper is one of the most important tools when editing pictures that were not created in Paint. It transfers the color under the dropper to the left (active) side of the color palette. A left click makes it the foreground color; right click is for background color. Pencil Author: Len Cabrera, May 2001, Updated Dec of 13

7 The pencil is the best choice for detailed editing because it only draws one pixel at a time (unlike the paint brush which covers more area). It works best in conjunction with "Zoom" (see below) Select Zoom There are two buttons to select portions of the image in Paint. The left button is "Freeform Select" which allows you to draw around the specific object to be selected. The right button is a standard select which draws a rectangle around an entire area to be selected. Once the area is selected, there will a dashed rectangle around it (even for free-form). From here, you can manipulate the selection using the "Edit" or "Image" menus or using the cursor. The usual reason to select portions of images is to copy it to the clipboard. In some instances, if an entire image is pasted into MS Paint for editing (e.g., removing background color), you may want to select the entire image to paste back into MS Photo Editor to save in a different format. There are two options available for both types of selection: Opaque (top) and transparent. The first causes the selected object to cover the existing picture (i.e., it keeps its foreground and background color). The transparent selection allows the existing picture to show through the background color of the selection (i.e., it only keeps the foreground). Selecting the "Zoom" tool puts a rectangle around the hour glass icon indicating the area that will be zoomed in on. The "View" menu can be used to customize the zoom settings (e.g., amount of zoom, show grid lines, show thumbnail, etc.). Zoom comes in handy when working on detailed images. MS Photo Editor - used for basic editing of all images, but not really for drawing or writing on the images like you can with MS Paint. Like MS Paint, the actual software is not very powerful but has the advantage of coming standard with Microsoft Office (97 and later, although you have to search for the application in later versions because it doesn't automatically install in the Start Menu folder). You can use it to convert between image formats, to touch up image color, to crop an image, or to set transparent colors. AutoBalance - allows the program to automatically balance the colors in the selected image by setting the best brightness, contrast, and gamma correction for each color (red, green, and blue). Usually, this feature is sufficient to tidy up pictures (whether taken from a digital camera or scanned from developed film). The tool can be found in the "Image" menu. Converting - saving an image in different file formats is simple in Photo Editor. With the image selected, go to the "File" menu and select "Save As " A screen will appear with Author: Len Cabrera, May 2001, Updated Dec of 13

8 various types of image formats towards the bottom. The "More >>" button will present additional options for the selected format such as compression and color quality. Paste as New Image - imports an image from the Windows clipboard into MS Photo Editor. This feature is used when copying bitmaps from MS Paint (rather than saving the file and opening it as a bitmap). It is also used when capturing Web graphics or other screen graphics using the "Print Screen" button on the keyboard (usually very top row, third button from the right). Windows help explains the use of the "Print Screen" button for screen captures. The tool can be found in the "Edit" menu. Set Transparent Color There are two uses for the "Set Transparent Color" tool. The first is the obvious reason: to set a transparent color. This is used to remove the background colors from images that are intended to stand out in presentations (e.g., unit emblems in PowerPoint slides). The second use of this tool is to eliminate the color problems caused by compression algorithms in JPG and GIF images (i.e., many shades of white, especially at the borders). Regardless of the intended use, if the desired transparent color also appears in the image, the "Set Transparent Color" tool can be used in conjunction with MS Paint. First, the background color is selected. A new window will appear to select "Color Similarity" and "Transparency." The former ranges from exact (only that color will be set) to 10% (allowing up to 10% error in the color value for each primary color: red, green, and blue). Usually the highest setting will be good enough. The "Transparency" entry ranges from 0 (no transparency) to 100 percent (completely eliminate the selected color). Again, set this to the highest (100%) setting. When the "OK" button is pressed, the transparent section is shown as a gray and white checker board. Continue to select colors as they appear in the background until they are all eliminated. Note: In some images (especially converting from black to white backgrounds), this process may not result in a decent quality image. Next, open MS Paint and color in the background with the color being set to be transparent. (This may require previous planning by pasting a bit of the image before starting to eliminate the color and using the "Pick Color" tool in MS Paint.) The image from MS Photo Editor can then be selected and pasted into MS Paint where "Flood Fill" is used to give the background a truly unique color. The image is the selected again and pasted back into MS Photo Editor (see "Paste as New Image"). The new background can now be set to the transparent color. Author: Len Cabrera, May 2001, Updated Dec of 13

9 III. Manipulating Digital Video. Special hardware is required to capture digital video in a format that can be manipulated by computer. For standard video sources (i.e., VHS or 8mm camcorders), you need a video capture card. The capture card allows you to plug in composite (RCA) video and audio cables or an S-video cable from the camera to the computer. Digital recorders can also use a video capture card with analog connections (RCA), but they are much faster with digital transfer that does not require a video capture card (Firewire). Regardless of how the digital video gets put into a computer format (AVI, MPG, or MOV), specialized software is required to edit digital video. Most of the software packages operate on the same basic principle. They allow incorporation of multiple video and audio clips, editing the length of each clip, and adding certain special effects such as fade in/out and transitions. You don't need to record an entire tape because video editing allows you to capture the exact section you want. If you're just interetsed in video or if your audio is annoying (e.g., aircraft background noise), you can remove the audio portion of the file. That helps to save disk space. Once the desired video segment is created, the file can be saved at the desired format (320x240 at 15 fps). Author: Len Cabrera, May 2001, Updated Dec of 13

10 IV. Incorporating Into Reports. Given the differences in file size and several other factors, still images and digital video are usually incorporated into reports and presentations in different ways. The sections below provide a general guideline for use in any Microsoft Office product. Stills - There are many ways to put still images into reports and presentations. The main difference between them is simply personal preference. In all the methods discussed here, the actual image is saved with the document so it no longer needs to be included in the folder when (if) the file is distributed electronically. Adding an Image - there are many ways to insert an image into Office applications. Here are three: Insert Picture This tool can be called from the "Insert" menu ("Picture", "From File " [see below]) or directly from the button above if it is on the drawing toolbar. The command brings up a typical Windows Explorer window which allows you to search for the image file you want to insert into the document. The number of types of files displayed will depend on which image format converters are installed (see your workgroup manager if your application cannot open the image that you want). Using this method to insert an image will keep it in it's original format. That is not always desirable (see "Paste Special" below). Also, in Word, this technique will (usually) default to inserting the image inside a paragraph ("In line with text"). That is helpful if you want to use tables to organize your pictures. Paste If an image is already in the Windows clipboard (e.g., copied a selection from MS Paint or MS Photo Editor), it can be inserted by using the paste function. The function is accessed from the button shown above which is found on the Standard Toolbar of all MS Office applications. It can also be used from the "Edit" menu. As with the "Insert Picture" feature, this function keeps the image in its original format. The picture properties assigned by the Office application will be the default for the particular format of image. Author: Len Cabrera, May 2001, Updated Dec of 13

11 Paste Special Rather than keeping the same image format by pasting it as described above, a better method (in Office) is to use the "Paste Special" feature (found on the "Edit" menu). A special window will appear with various options on what to paste the image (or anything on the clipboard) as. As it explained in the window reproduced below, the "Picture" format is best for MS Office. It takes less disk space, displays quickest on the screen, and is better for printing. Usually, this method will paste the image in the "Top and Bottom" layout (explained below), which is annoying, but can easily be changed. Image Properties - working with images (or objects) in MS Office applications requires familiarization with several properties and tools. Properties are attributes that determine how the image will interact with other objects and text in the document. They can be visible all the time, some of the time, or not at all. Tools are either chosen from the menu bar or a button on a tool bar and manipulate the properties. Below are some of the basics frequently required when writing reports. Anchor The anchor is a non-printing character that appears in the left margin indicating which paragraph the image is associated with. The image will generally stay on the same page in the same relative position to the paragraph. If the anchor does not appear when an image is selected, click on the paragraph mark ( ) in the "Standard" toolbar to display all non-printing characters. The anchor will move automatically if the image is moved, but it can also be moved by itself to change which paragraph an image is associated with without moving the image itself. To do so, move the cursor over the anchor. The cursor will change and appear as four, black directional arrows underneath a standard white arrow. Click on the anchor and drag it to the desired location. Crop This tool changes the viewable area of an image. The only place it appears if the "Picture" toolbar which (usually) appears automatically when a picture is selected. Author: Len Cabrera, May 2001, Updated Dec of 13

12 When the tool is activated, the cursor will change and display the symbol above at the tip of the standard white arrow. By left clicking on the image in any of the sizing marks (see "Size" below), the image can be cropped in or out. Going in basically hides the area between where the border(s) started and ended. Going out will reveal the original image. The border can be extended beyond the original image size. Doing so will have white space between the original image and the new borders. Edit Picture - a function that allows direct editing to an image. It is an option found by right clicking on an image. DO NOT USE THIS TOOL. Editing the picture within MS Office automatically changes the format, usually for the worse. It also converts most text direction to the horizontal so it ruins the vertical axis on plots. Layout - as mentioned in the "Adding an Image" section, there are several ways an image can appear in a document. The most common are "In Front of Text" and "In line with text" (although "Top and Bottom" is an unfortunate default for certain methods of inserting an image). The former is selectable from the layout button on the "Picture" toolbar (show on right). It allows the image to float over text and does not force text and objects to constantly shift as the image is moved. The best way to then place this image is to put blank paragraph marks behind it and group them together using the "Keep with next" property ("Format", "Paragraph", "Line and Page Breaks"). This is especially useful when tying a title (i.e., text) with the image. The "In line with text" layout keeps the image inside the paragraph. In order to set this layout, right click on the image and select "Format Object " then select "In line with text" from the "Layout" tab. This layout is required for inserting images into tables (see below). Unfortunately, this layout is only available with some picture formats and cannot be used for images composed of multiple drawing objects. The figure below shows the difference in appearance between the two layouts discussed. "In Front of Text" "In Line with Text" Size - There are two ways to size an image. The simple way is to use the mouse. When an image is selected, sizing marks appear in the corners and the sides (see figure above). The cursor will change in these different areas to allow the picture to be resized. The sides only resize width; the top and bottom only resize height; the corners resize both. For some image formats, resizing from the corners automatically preserves the aspect ratio (i.e., the ratio between the height and width). A more accurate way to size images is to use the "Size" tab on the "Format Object " window. This window allows sizing to be relative (by percentage) or absolute (inches, pixels, etc. based on the Office default). This method is useful when incorporating several images because it allows Author: Len Cabrera, May 2001, Updated Dec of 13

13 consistency. For example, the "Lock aspect ratio" box can be selected and then all images on a page can be forced to have the same width. Another option is to have all images on a single line have the same height. Tables - Rather than using the "Keep with next" paragraph property to manage images, tables can be used to keep images and text together if using the "Allow row to break across pages" field in the "Table Properties " window (right click on the table). This technique is only available for images that can use the "In line with text" layout as discussed above. This tutorial is not intended as a lesson on using tables. Within the table, images and text can be manipulated just as described throughout this document. Video - There also are many ways to put video clips into reports and presentations, but usually the file sizes limit that ability. The best solution is to link text or objects in the document to the video clip. That means the actual video file must be included in the folder when (if) the file is distributed electronically. To create a link, highlight the desired text or object and right click. Then select "Hyperlink " (or get it from the "Insert" menu or press Ctrl+K). A new window will open. Select "File " from the mid-right side of the window. Yet another window will open. Use the new window to browse for the image file to link to. Note: Be sure to keep the address relative in the "Insert Hyperlink" window. For example, rather than using "C:\tests\040\video\scene1.avi" for the link, use "\video\scene1.avi". That way the link will search in the same folder as the document and it can be copied to other locations (like CD-Rs). Note: The hyperlinks work well in Office documents, but they do not transfer to Adobe Acrobat. The color change (usually blue, underlined text) gets copied to Adobe, but the link itself does not. The links have to be re-established in Adobe. Author: Len Cabrera, May 2001, Updated Dec of 13