PICTCompressor is an application which allows you to compress images using QuickTime. It is meant to be used as a tool for testing image compression components, and can also be used for compressing PICT images. It is not meant to be an image processing application, or an example of a recommended human interface for an image compression application.
----------------------------- Using PICTCompressor -----------------------------
Here is how you use PICTCompressor to compressor PICT images. Use the "Open…" item in the file menu to open an existing PICT file. If you have an image that is stored in some other format, you can open it with another application, select the image ( or a piece of it), copy it and paste it into a new document in PICTCompressor. Now you have an image to work with. To compress it, choose the "Compression…" item under the image menu. This will bring up a dialog box for choosing the compression parameters. It contains two pop-up menus and a slider control. The first pop-up menu allows you to choose the compression format you want to use. You will see the standard compressors included with QuickTime, plus any you may have written yourself or installed from third parties. Some compressors allow you to limit the color resolution of the compressed image to save space, others do not allow this. If the compressor you picked, allows you to specify a color depth, the available color depths appear in the second pop-up menu. Choose the one which gives you the best color representation that you want for the compressed image. Now set the slider to the quality level you desire. Higher quality images look better, but may be larger than lower quality images. The relationship between quality and size may not be linear for a given compressor, and will vary based on the content of the original image. It is good to experiment to get the best results, although picking something in the center of the range is usually a good starting point. After you click the okay button, the image will be compressed, and the result will be decompressed and displayed in a new window called "Compressed (name of the original image)". Repeating the compression step, replaces the compressed image with the one with the new parameters. If you want to save the compressed image at any point, just use the save menu item and the compressed image will be saved as a compressed PICT. The compressed PICT can be displayed by any application which supports PICTs on any Macintosh with QuickTime, and the decompressor for the compression format used installed. On other systems a default picture reminding the user that QuickTime is required is displayed instead.
----------------------------- Other features -----------------------------
Zooming
You can set the zoom factors for the active window using any of the three zoom menu items under the image menu. "Zoom in" makes the image 10% larger and "Zoom Out" makes the image 10% smaller. The "Zoom…" menu item allows you to type in a magnification factor ( expressed as percent of the original ) for both axes, or for horizontal and vertical independently.
You can quickly display the active window at its actual size (100% zoom factor) by selecting the actual size menu item in the image menu.
If you want to see the entire image, you can enable the Fit To Window item in the image menu and the image will be fit to the window, regardless of its size. Note that this does not preserve the aspect ratio of the image, and it will appear distorted. When you return to actual size, or reset the zoom factors so the are the same for horizontal and vertical this will be restored.
Statistics
For a display of statistics about the original and compressed images, use the statistics menu item, which displays a window with information about both images. It tells you which compression format is used for each image ( note that the original image, may already be compressed). The quality setting ( only for compressed images), which is a number between 0 (lowest quality) and 3.99 ( highest quality). The special value of 4.00 means that the compression process was lossless. The resolution of the image is also given in pixels. Note that the screen size may be different if the image is not a 72 dot per inch image, If it is not a 72 DPI the resolution in DPI, this is indicated in the center of the status bar at the top of the window, next to the magnification percentage. The size of each image in bytes is also displayed. This size is the actual number of bytes in the entire PICT file. The compression and decompression times are also given, in milliseconds.
Grid
If you wish to display a grid over your image for referencing pixel locations you can use the Show Grid item in the image menu. If you hold down the option key while selecting this item, a dialog will come up allowing you to set the grid interval in pixels.
Printing
You can print the contents of the original or compressed image, based on which window is active when you choose the print menu item. Note that the image is printed so that it fits on the page, and there are no page setup options.
Making selections
You can select a portion of an image by clicking and dragging the mouse in the image area. ( Note that auto-scrolling does not work). You can however, resize the selection area by grabbing the sides of it or the handles in any corner of the selection rectangle ( you can tell when you've got it because the cursor will change into a two-headed arrow) You can also move the selection rectangle by dragging inside of it ( the cursor will be a hand ). Once you have a selection, it can be copied for pasting into other applications. If you want to compress only part of an image, select it, copy it, and then close the original window and paste it into a new original window, which can then be compressed. Note when you paste into an image, the entire existing image is replaced with the pasted in image.
Previewing
When you choose open from the file menu, PICTCompressor uses the StandardPreview feature of QuickTime to allow you to see a preview of PICT files you may want to open. If a PICT file does not have a preview, you can use the "Create" button in the StandardPreview dialog box to create a preview for the selected file. If you want to open files with the standard GetFile box and not have previews, you can hold down the option key when choosing open and the StandardGetFile will be used instead.
When you save a file with PICTCompressor, the preview picture can be created when the file is saved. This is done when the create preview check box is checked in the StandardPutFile dialog when you do a save.
----------------------------- Advanced Features -----------------------------
Importing other image formats
PICTCompressor allows you to import images in certain other formats. Currently the only one supported is JFIF, which is the JPEG File Interchange Format specified by C-Cube Microsystems as a format for storing JPEG compressed images. To import a file of a certain type choose the Import menu item. This will allow you to choose one of the supported image formats. This is then followed by a open file dialog, which will show you ALL files of ALL types. You must select only files which are in the format which you are specifying ( this is
to allow for interchange with other machines, since the file types may not be set correctly).
Storing other image formats
PICTCompressor supports a few other formats for compressed data for the purpose of interchange with other machines. The formats currently supported are JFIF and PostScript Level 2, both of which are valid only for JPEG compressed images. To select one of these, hold down the option key while selecting the Save as… item from the file menu, and select the desired format from the pop up menu which appears in the standard putfile box.
Choosing a specific compressor
Normally, when compressing an image, PICTCompressor asks for any available compressor for the selected format, which will give you the fastest compressor for that format. If you want to pick a particular compressor for a given format, you can hold down the option key when you select the "Compression…" menu item, and each compressor will appear in the compression pop-up menu individually.
Image buffer settings
PICTCompressor uses an offscreen image buffer to store the images before they are displayed. It is the size of the image in pixels ( regardless of the resolution, i.e. for a 144 DPI image which is 640x480 pixels, the image buffer is that size, although the displayed image is only 1/4 of that size when displayed on the 72 DPI monitor.), and it defaults to 32 bits deep. If there is not enough memory to allocate this buffer, a dialog will appear warning you of this. At that point you can choose a lower depth for the image buffer ( which may sacrifice some color resolution in your image, depending on its content) or to not use an image buffer. If you don not use an image buffer, the compression must be done from the screen, which means you are limited to the color depth and pixel area of your monitor, which may not be as good as an offscreen image buffer. You can reset the image buffer parameters at any time from the "Image…" menu item. This allows you to enable or disable the image buffer, set its pixel depth or if it is less than 16 bits/pixel, to select which color look up table to use.
