MacWorld 1998 February

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This is a very brief reference manual for A Smaller GIF†. It can be found online at http://www.peda.com/smaller/man.html. The manual has two sections. The first section describes the menus; the second section describes the windows. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - We begin with an overview of the menus available while using A Smaller GIF. Apple Menu * About A Smaller GIF... displays the start-up screen. It may be dismissed by pressing any key. The start-up screen shows the program's version number on the left and the registered user's name on the right. File Menu * Open... allows you to open an animated GIF to work with. After opening a file, three windows will open (a preview window, an animation controls window, and a frame controls window). The windows are described in the Windows section of this manual. An additional work window (the range controls window) may be opened via Range Controls... in the Animation menu. * Close Window closes the foremost window. Closing any of the windows for a particular animated GIF will close all of the windows associated with that animated GIF. * Save saves the current document after trying to minimize the amount of disk space the animation uses. A Smaller GIF can reduce the amount of space an animation uses without changing its appearance in any way, as GIFs are stored using a lossless compression format. Many of the GIF utilities available do not maximally compress GIF files when they are saved. Even A Smaller GIF is not guaranteed to fully compress a GIF file. Currently, the program uses a number of techniques to reduce the size of the resulting GIF file. Later versions of this program may incorporate additional compression techniques. Some techniques may produce files that are not compatible with viewers that do not fully implement the GIF standard - you have some control over the techniques employed via the preferences window. * Save As... is similar to Save, but allows you to save the file using a new name, so that you may keep your original file intact. * Test Compression compresses the GIF file without actually saving it. After compression, it will report the file size that would have been acheived if the file was actually saved. * Register... is used to register the program. For more registration information, please see our registration page. * Preferences... opens the preferences window, which allows you to control the compression techniques used. You may also edit your own standard GIF comment by using the preferences. See the section on preferences for more information. * Quit exits the program. Edit Menu The edit menu allows you to cut, copy, and paste text into the various text fields used. Animation Menu The animation menu is available after you have opened an animation. * Add Standard Comment prepends the exit comment with your standard comment. You may modify your standard comment via the preferences window. * Remove All Comments removes all GIF comments from the animation. * Standardize Comments first removes all GIF comments from the animation, and then adds your standard comment. * Deinterlace All Frames deinterlaces all of the frames of the animation. On many platforms, Netscape Navigator (versions 2 and 3) flickers considerably when displaying the first frame of an animated GIF which is interlaced. Subsequent interlaced frames don't cause flicker, but do slow updating. On both the Macintosh and Windows platforms, Microsoft Internet Explorer (version 3) handles interlaced animated GIFs well. * Range Controls... opens a range controls window for the animation. The range controls window allows you to easily apply operations to every frame within a selected range of frames. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - We illustrate the remainder of the program by discussing what happens when you open the provided "GrafEq Ad.gif" file that is supplied as part of the download package. The file has already been processed by a utility which claims to shrink your GIF files. Preview Window The preview window, entitled "GrafEq Ad.gif Preview", displays a preview of the animated GIF. If you enlarge the window, you will see the entire window title. The preview image will be centered within the larger window, and surrounded by the GIF's background colour. The keyboard's arrow keys may be used to navigate, as described below: * Press the right arrow key to advance the preview by one frame. Hold the right arrow key down to fast-forward through the animation. * Press the left arrow key to rewind the preview by one frame. Hold the left arrow key down to rewind through the animation. * Press the down arrow key to play the animation forward, at normal speed. Press the key again to fast-forward through the animation. * Press the up arrow key to play the animation backward, at normal speed. Press the key again to repidly rewind through the animation. * Press the space bar to toggle preview playback. If the preview is playing, the space bar stops the preview. If the preview isn't playing, the space bar starts playing the preview forward, at normal speed. * Press the escape key to stop the preview from playing. If the preview reaches the end of the animation while playing forward, it will resume from the beginning. If the preview reaches the beginning while playing backward, it will resume from the end. Animation Controls Window The animation controls window, entitled "GrafEq Ad.gif Animation Controls", is used to control the overall animation. Although you often can't see the entire title, the window's visual appearance sets it apart from the other windows. * Size: 140x60 (6.1K) displays the size of the animation. In this case, it is 140 pixels wide, 60 pixels high, and uses approximately 6.1 kilobytes of disk space. * 31 Frames (0:07.20) displays the length of the animation. In this case, it contains 31 frames. If the animation is played at normal speed, on a machine capable of playing the animation at normal speed, it will last 7.2 seconds. * Loop forever controls the looping aspects of the animation. This animation is set to loop forever. Other possibilities include playing once, or looping a fixed number of times, from once to 65,535 times. * 24 colours displays the number of colours used in the animation. * Background Colour FFFFFF displays, visually and textually, the background colour of the animation. Web browsers tend to ignore this, and opt to use the web page background instead of the background specified here. As the background given here is used in the preview, this control allows you to see the effects of different page backgrounds. The textual description is given using HTML syntax - the colour is given as <red><green><blue>, with each component given as a two digit hexadecimal number. * Starting Comment displays the GIF comment(s) that precede the frames of the animation. You may edit the comment. Normally, one chooses to put comments after the animation frames, by using the next control. Starting comments will delay the arrival of the first frame. * Ending Comment displays the GIF comment(s) that follow the frames of the animation. You may edit the comment. Frame Controls Window The frame controls window, entitled "GrafEq Ad.gif Frame Controls", is used to control the current frame of the animation. Although you often can't see the entire title, the window's visual appearance sets it apart from the other windows. * Frame 1 0:00.00 identifies the current frame. In this case, the current frame is the first frame, which also starts at 0 seconds into the animation. You may jump to any frame in the animation by entering a frame number. * The frame slider appears next. It visually displays your position in the animation. You may position yourself to any frame by dragging the thumb with the mouse. * The seven playback controls are displayed next. The edgemost controls rapidly rewind and fast-forward the preview through the animation. The next pair plays the animation, at normal speed, backwards and forwards. The innermost pair rewind and advance the preview through the animation one frame at a time. The center control halts automatic playback. * Duration 0:01.00 controls the duration of the current frame. In this case, the current frame lasts 1 second. * User Input specifies if the user, by giving some sort of input, may cause the animation viewer to advance to the next frame before this frame's duration has expired. If checked, and the user gives input while this frame is displayed, the viewer should immediately advance to the next frame. If this frame has a duration of zero seconds and the control is checked, the viewer should not advance until user input is given. A Smaller GIF ignores this feature of GIF animations, as do most other viewers. * Interlaced controls whether the current frame is interlaced. * Comment shows the comment(s) that immediately precede the current frame. Normally, comments are put at the end of the animation by using the Exit Comment control in the animation controls window. Range Controls Window The range controls window, entitled "GrafEq Ad.gif Range Controls", allows you to work with frames as a group. With this window, you may apply an operation to every frame within a range of frames without manually performing the operation on each frame yourself. Although you often can't see the entire title, the window's visual appearance sets it apart from the other windows. The range controls window can be in one of several modes. The individual modes will be discussed later. We will first focus on the controls that are common to all modes. * Scale Durations is a popup menu that lets you control which mode the window is in. * Frames 1 to 31 (inclusive) displays the selected range of frames. You may select a new range of frames by either typing in a new frame range or using the slider below. The arrow keys may also be used to select a range of frames: the left and right arrow keys change the selection's lower endpoint, while the up and down arrow keys change the selection's upper endpoint. Whenever an action is applied using this window, it will only affect the frames within the selected range of frames. We will now go over the controls in each of the available modes. Scale Durations This mode allows you to change the duration of many frames at once. The duration of each frame in the range is multiplied by the specified scaling factor. o Scaling Factor: 1.00 specifies the scaling factor to be used. You can enter a new scaling factor or select a scaling factor between 0.1 (ten times faster) and 10.0 (ten times slower) by using the slider below. o More Choices lets you have more control over the process. Click this button to reveal more controls. o Scale scales the duration of the selected frames. o After Scaling: specifies the minimum and maximum duration of each frame, after scaling has been applied. This control is shown by selecting more choices. To make all of the selected frames have the same duration, enter the same value for minimum and maximum duration. A non-zero minimum duration is advised, as a frame with zero duration may not be displayed by some viewers. o Fewer Choices removes the advanced controls from display, after reseting them to their default values. Remove Comments This mode allows you to remove comments from a range of frames. o Remove Comments removes all comments from the selected range of frames. Deinterlace This mode allows you to deinterlace a range of frames. o Deinterlace deinterlaces all of the selected frames. Preferences Window The preferences window, opened by selecting Preferences (under File), is used to * control which GIF compression techniques are tried, as well as to * edit your standard comment. The popup control in the top left corner of the window selects which preferences you wish to review. Preferences are stored on disk in the registration file. Comments on each of the available preferences follow: * GIF Optimization The GIF optimization controls allow you to trade off compatibility against file size. Maximum compression is usually achieved by keeping all controls checked and to pick transparencies from an ultralow band. For good compatility with browsers you can uncheck Omit frame terminators, uncheck Use a small rectangle for the first frame, and choose transparencies from the superlow band. Doing so will normally increase file size slightly and keep compatibility with older versions of the common browsers. To see expected compatibility, click on the Compatiblity... button to bring up an interactive window which will let you see the interaction between the compression options and browser compatibility. Small, simple animations are more generally compatible than long, complex animations since small, simple animations are less likely to expose a bug in a browser. We would like to thank users for keeping us informed of bugs in the browsers out there so we can add ways to avoid the problems that may occur. The good news is that with each release, the browsers are usually getting better at displaying animated GIFs. o Omit frame terminators specifies whether frame terminators may be omitted. Most GIF viewers ignore frame terminators and opt to determine the end of a frame by counting the number of pixels decoded. Viewers are forced to do this since a moderate number of GIFs do not include frame terminators. With this option selected, the files are slightly smaller, but do not follow the GIF specification strictly. Internet Explorer for Windows (and other Windows-based Microsoft software) requires frame terminators. o Exclude (0,0) from frame rectangle specifies whether the top left corner of encoded frames must be the top left corner of the animation. A Smaller GIF only encodes differences between frames, so the upper left corner is often not included by default. Checking this will generate smaller GIFs. Produced GIFs will not be compatible with version 2 of Internet Explorer for the Macintosh if this control is checked. o Use interframe transparency specifies whether transparency may be used to encode pixels that do not change from one frame to the next. Many GIF utilities do not deal with transparency very well, so unchecking this may allow you to edit the GIF before putting a final version up for people to view. As an example, GifBuilder for the Macintosh will display, when looking at a particular frame of an animation, transparent areas as being transparent (rather than taking into account the previous frame, as a simple viewer would). If you were to play the animation back in GifBuilder however, the animation will be properly displayed. Many other GIF utilities behave similarly. o Pick a transparency index from the ultralow A band partially specifies which index should be used for transparency. This control is provided so that you may work around display bugs in various browsers. The general rule is that the higher bands will produces larger GIFs. Netscape Navigator 2 and 3 for the Macintosh both have some trouble displaying GIFs that use transparency. Picking transparency indices from the superlow band (which increases file size slightly) will usually avoid such problems for GIFs that use transparency mainly for interframe compression. A higher band is sometimes needed for GIFs that use transparency visually (so that you may see moving objects against a web page's background). There is a rumour going around the Netscape Navigator 3 for the Macintosh cannot display such animations (regardless of which tool is used to create them), but we have had success with such animations by using transparencies from higher bands. o Compatibility... opens up the Compatibility window, which lets you interactively see the interplay between the compression options and browser compatibility. With the compatibility window, you may control the compression options indirectly by controlling the compatibility directly (or vice-versa). Note that the compatibility reported is pessimistic, as it is for long, complex GIFs. Small, simple GIFs will likely be compatible regardless of the compression options, as such animations are unlikely to expose bugs in the browser. The estimated audience figure comes from statistics gathered from the www.peda.com web site. More Info... displays information regarding the Compatibility window. * GIF Comments o Standard GIF Comment shows your standard GIF comment. You may quickly add your standard comment to an animation by selecting Add Standard Comment from the Animation menu. The default comment is "Shrunk by NAME on DATE, using A Smaller GIF vVERSION." + "NAME" expands to the registered user's name, + "DATE" expands to the current date, and + "VERSION" expands to the current version of the program. * Startup o When appropriate, show depth warning on startup controls whether A Smaller GIF will warn you when you start up on a display with 256 or fewer colours. If checked, A Smaller GIF will warn you that animation previews may be inaccurate with the current display settings, and that image processing is not affected. For more information visit the program’s web page at http://www.peda.com/smaller/. ______________________ †The Graphics Interchange Format© is the Copyright property of Compuserve Incorporated. GIF(sm) is a Service Mark property of Compuserve Incorporated. †A Smaller GIF™ is a trademark of Pedagoguery Software. †Netscape Navigator is a trademark of Netscape Communications Corporation. †Internet Explorer is a trademark of Microsoft. All other displayed trademarks are the property of their respective holders.