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Text File | 1998-06-28 | 14KB | 399 lines

_____________________________________________________________________________ P h o t o F i l e r Picture thumbnailing extension for the Filer Written by David Thomas for Sliced Software, © 1998 version 1.00 (28 Jun 1998) _____________________________________________________________________________ ____________ Introduction ____________ PhotoFiler is a utility program which adds the ability to ‘thumbnail’ pictures to the Filer. With PhotoFiler loaded, a miniature version of the picture is shown in directory displays in place of the usual file type icon. This is very useful for organising collections of pictures, as it enables you to rapidly identify the contents of a picture file just by looking at its icon. In addition to thumbnailing, PhotoFiler provides additional controls over the presentation of icons in directory displays. You can define your own icons for directories which will be used instead of the usual directory sprites. This is ideal for providing a graphic representation of a directory’s purpose. PhotoFiler also attempts to alleviate a long-standing problem - that of the pling (‘!’) character in front of application names. These can hidden from view in directory viewers, giving neater looking directory displays. PhotoFiler requires RISC OS 3.6 or later. RISC OS 3.5 is supported, if the SpriteExtend 0.99 and DrawFile 1.46 modules are available. PhotoFiler is SHAREWARE. ________ Features ________ · Sprites, JPEGs and DrawFile pictures are thumbnailed in the background and displayed in place of the file type icon. · Full control over the dithering of thumbnails is provided for Sprites and JPEGs. · Pictures which are found to be faulty are shown with a ‘warning’ symbol. · Directories can be given customised sprites by merging a sprite into the common sprite pool. Sprites can be provided for the four possible directory states of open/closed and selected/unselected. · The pling symbol (‘!’) can be removed from the start of application names, giving neater looking directory displays. This modification occurs in display only so that sorting orders are not affected. · PhotoFiler is transparent in operation, written in 100% ARM assembler. None of the Filer module’s code is modified, meaning that PhotoFiler uses very little memory itself. _________ Interface _________ Icon Bar Icon ¨¨¨¨¨¨¨¨¨¨¨¨¨ SELECT on the icon bar icon opens the Control Panel. MENU opens the icon bar menu. Control Panel ¨¨¨¨¨¨¨¨¨¨¨¨¨ The control panel is available by clicking SELECT on the icon bar icon. Show Sprite thumbnails When set, sprite files will be thumbnailed. Simple dithering Performs a simple dithering technique on the thumbnail. Application sprites Forces thumbnailing off for sprites that are part of applications. Show JPEG thumbnails When set, JPEG images will be thumbnailed. No dithering Quickest, but lowest quality, thumbnails. Simple dithering Medium speed, medium quality, thumbnails. Error diffusion Slowest, but highest quality, thumbnails. (Note that you’re unlikely to notice any great speed/quality difference between these last two options). Show Draw thumbnails When set, DrawFiles will be thumbnailed. Hide application plings When set, applications will have their initial pling character (‘!’) removed from view. Icon Bar Menu ¨¨¨¨¨¨¨¨¨¨¨¨¨ Quit -> Control panel only Removes PhotoFiler’s control panel only, the module - which does the work - will remain active. -> All of PhotoFiler Removes PhotoFiler completely from memory. ________ Features ________ Thumbnails ¨¨¨¨¨¨¨¨¨¨ PhotoFiler generates thumbnails on the fly as soon as you open a directory viewer containing Sprites, JPEGs or DrawFiles. The first thing you will notice upon opening such a directory is that the picture’s usual file icon is shown in shaded grey until the thumbnail is generated. You will normally only see this icon for a fraction of a second, especially on faster machines, as even the largest thumbnails take only a few seconds to load and render. Once the thumbnail is ready, it is displayed in the place of the icon in the Filer window. Thumbnails are processed in the background so you can continue to use the desktop whilst thumbnailing is taking place. Only icons that are visible on screen are ‘seen’ by PhotoFiler. This means that if you scroll a directory viewer to reveal more icons, they will then be noticed by PhotoFiler and processed. PhotoFiler can handle any number of thumbnails in any number of directory displays simultaneously, although things will slow down proportionately with the number of directory displays that are active. PhotoFiler always attempts to generate the largest size thumbnail it can, given the aspect ratio of the picture and the amount of space available for the thumbnail in the Filer window. The maximum size of a thumbnail sprite is 172 by 74 OS units, which equates to a maximum of 86 by 37 pixels in a typical square pixel mode. Due to the way Filer windows are laid out, any thumbnails bigger than that would be displayed incorrectly and obscured by the text of the filename. Thumbnails are always created in the current screen mode so that the user has control over the quality vs. memory tradeoff. If you change screen mode, thumbnails will not be re-rendered to the new mode. Sprite Thumbnails ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ Sprite thumbnails are thumbnailed using RISC OS’s sprite scaling features. When the ‘Show application sprites’ option is off, PhotoFiler will not generate thumbnails for files with the word ‘Sprites’ in their name. This stops most sprite files belonging to applications being shown. (Note that this check is case-sensitive). If a sprite has no palette present then the default desktop palette is used. This matches the behaviour of RISC OS Paint when its ‘Use desktop colours’ option is on. Only the first sprite in any multiple-sprite file will be shown. JPEG Thumbnails ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ The JPEG rendering feature of RISC OS 3.6 and later is used to generate thumbnails for JPEG images. JPEG images are always tested for completeness and integrity before being rendered. This means that partial or corrupt JPEG files will not be presented as thumbnails. The RISC OS JPEG rendering calls are quite particular about the files that they will render. Images with certain non-standard settings in the file header will often be rejected. You may wish to obtain a copy of the JPEGTrans¹ utility which can clean and optimise JPEG images. Progressive JPEGs cannot be thumbnailed, unless they are first converted to normal JPEGs by using JPEGTrans. ¹ Freeware, by Chris Egan of Skullsoft. http://www.eganc.demon.co.uk/ DrawFile Thumbnails ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ PhotoFiler uses the DrawFile module, built into RISC OS 3.6 and later, to generate thumbnails of DrawFiles. Before being thumbnailed, the DrawFile is (mildly) validated to ensure that it can be rendered correctly. Any file that fails the validation will be shown with the ‘error’ symbol. The DrawFile module performs no anti-aliasing when scaling down, so thumbnails may look innacurate with respect to the original file. This is especially evident if ‘Thin’ lines are used in the DrawFile. If fonts are used in the DrawFile, then a large font cache will speed things up. ________________________ Custom Directory Sprites ________________________ PhotoFiler can adjust the sprite used by the Filer to represent directories. This is done by defining a new sprite for each possible directory icon state. Sprite name Small sprite name ¨¨¨¨¨¨¨¨¨¨¨ ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ Directory closed, unselected #dirname sm#dirname Directory closed, selected $dirname sm$dirname Directory open, unselected %dirname sm%dirname Directory open, selected &dirname sm&dirname If no sprite is found for the current sprite state, then the Filer’s default display will be used. (This behaviour isn’t ideal, and may be revised in a future version). Note that when a custom directory sprite is in use, the text of the icon will not be inverted when selected as usual. _________________________ Hiding Application Plings _________________________ With the ‘Hide application plings’ option selected, the names of applications displayed in Filer windows will be adjusted so that their initial pling character (‘!’) is removed. The advantage of this is that it gives cleaner looking directory displays and is potentially less confusing for novices. The character is only removed from the display of the name, it does not affect the physical name of applications on your disc or in any other part of the system. Using this option will not affect the sorting order of directory displays. _____ Notes _____ Suppressing Thumbnailing ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ Holding down Ctrl when opening a new directory display will suppress thumbnailing for that directory. Automatic Quit ¨¨¨¨¨¨¨¨¨¨¨¨¨¨ Adding ‘-autoquit’ to the last line of !PhotoFiler.!Run will make the front- end automatically quit once the module is initialised. This is useful for use in desktop boot sequences. Sprite Cache Dynamic Area ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ Even if you use the ‘All of PhotoFiler’ option to quit, PhotoFiler will not fully remove its ‘PhotoFiler sprites’ dynamic area. This is not a bug. When PhotoFiler is active it points the sprite area control block of each newly created directory display directly to its own sprite area. If PhotoFiler is removed, these pointers remain in place. Removing the sprite cache dynamic area whilst these directory displays are still in use would cause a crash, so the area is in left in place but reduced in size as much as possible. If PhotoFiler is later restarted, then it will automatically take over any existing sprite cache area. Bugs in RISC OS ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ Unfortunately, PhotoFiler is affected by a number of faults in RISC OS. They are detailed here to explain some of PhotoFiler’s more esoteric behaviour. 1. There is a bug in both current variants of the SpriteExtend module - the RISC OS module which deals with JPEG images. The bug is three redundant instructions which perform a read from an assumed location in the controlling task’s wimpslot. This causes an ‘abort on data transfer’ exception if the calling application has less than 24K of wimpslot. Since PhotoFiler is not a wimp task, it has no wimpslot, so calling SpriteExtend to render JPEG images will always fail. PhotoFiler automatically fixes this bug by copying the SpriteExtend module into RAM and disabling the redundant instructions. This fix takes approximately 75K of memory. 2. There is another bug in RISC OS’s own sprite handling code which causes apparently random crashes. PhotoFiler includes a work-around fix for this. The net result of this is that PhotoFiler has to claim at most 4K more sprite memory than it actually needs. 3. And again, there is another bug in SpriteExtend which means that JPEGs which scale to one pixel in either thumbnail dimension will be rejected in order to prevent a machine crash. ___________ Limitations ___________ · PhotoFiler works by filename alone, and for reasons of speed does not monitor file operations, so if you delete a picture then rename another file or directory to the same name, the previous thumbnail will be used for that object. · Pictures are loaded whole into memory before being rendered. Pictures which are too large to load will be shown with the ‘warning’ icon. · If PhotoFiler should run out of memory, then it will start showing thumbnails with the ‘warning’ icon. If memory is in very short supply then PhotoFiler will ignore the icons completely. · PhotoFiler slows down the window redraw speed of the Filer. _____________ Compatibility _____________ It is unlikely that PhotoFiler will work in conjunction with any other programs that tries to provide the same sort of functionality. This includes programs such as Album, ProFiler and Filer+, for example. Utilities such as (my own) QuickFiler will work, as it services a different area of functionality. ______ Future ______ - Support for ArtWorks files. - Resolution of first limitation (see above). ________ Versions ________ 1.00 (28 Jun 1998) - First general release. _______ Credits _______ Many thanks to go to Justin Fletcher for his original source upon which this program is based and to the brave souls who took part in the testing of prerelease versions. Thanks to Andrew Clover for the WimpSWIVe module. _______________ Sliced Software _______________ Sliced Software is an Acorn Registered Developer. _________ Copyright _________ This software (“PhotoFiler”) is copyrighted work of David Thomas, it is supplied to you, the user, “as is”; you use this application entirely at your own risk. The author makes no warranty as to the fitness of this software for any purpose. In no circumstances will the author be liable for any loss arising from the use or inability to use this software. THIS SOFTWARE IS SHAREWARE. PLEASE ABIDE BY THE SUPPLIED CONDITIONS OF USE. _____________________ Contacting the Author _____________________ If you have any comments, bug reports or suggestions for future versions then you can contact me via: Post: Mr D.P. Thomas 20 Rosebery Avenue Waterloo Liverpool L22 2BH Mail: photofiler@sliced.demon.co.uk Web: http://www.sliced.demon.co.uk/software/photofiler/ If you have a question, then please check it has not already been answered in this documentation before mailing. _____________________________________________________________________________