HiRISE Operations Center

Department of Planetary Sciences
University of Arizona
Tucson, Arizona

HiView User's Guide
Reference

Preferences

The Preferences dialog provides several sections for managing the HiView configuration settings. The settings are saved in a configuration file that is updated when changed settings are Applied. The configuration file also records values that are not Preferences settings - such as the layout geometry of the application, and the directory pathname for the last local file that was opened - that are written just before the application quits.

The configuration file is named HiView.ini and is located in the .config/UA_HiRISE directory under the user's home directory on Mac and Linux systems; on MS/Windows systems the configuration file is located in the user's "Application Data" directory under the "Documents and Settings" directory. The contents of the file is plain text describing the HiView application settings. The configuration file settings are read when HiView starts up. If the file does not exist - for example, when HiView is first run on a host system - the file is created and initialized with the HiView Default settings. The file should not be changed outside of HiView. If the file is removed for any reason HiView will recreate it as if the application were being run for the first time on the host system.

All Preferences sections have the same basic functionality. The Rendering section, above is used as an example to describe common controls.

The Dialog Window Header is provided by the host system window manager, so its style may be different than the example provided here for a Mac system. The name of the dialog - "HiView Preferences" - will always be included in the window header. Part of the Window Header style is the appearance of window controls. One of the controls will close the dialog. The dialog can also be closed with the ⌘W keyboard shortcut on Mac systems; the key combination is Ctrl+W on other systems. If the dialog is closed when there are any settings changes that have not been Applied a dialog will be presented asking if the unsaved changes should be applied or discarded, or if the window close should be canceled so the Preferences can be examined again.

At the top of the dialog window, immediately below the Window Header, is a row of tab buttons used to select a Preferences section. When a tab button is clicked, the panel for the section named on the tab will be brought to the front. Each section panel has its own particular settings controls.

The Restore Value button is a circular green arrow icon button that appears to the right of a value field whenever it contains changes that have not been Applied. If the button is clicked the field will be restored to its value from the last time it was Applied.

At the bottom of each section pane is an Apply button. The Apply button will only be enabled when there are changed settings in the section that have not been saved. Clicking the Apply button will save all changes made to section settings in the configuration file and apply them to the application operation. All Restore Value icon buttons on the section panel will disappear and the Apply button will become disabled again.

Note that the Apply button only affects settings for the visible section. Each section panel has its own Apply button.

At the bottom of each section pane is a Defaults button. The Defaults button will only be enabled when there are settings in the section that do not have the HiView default value. Clicking the Defaults button will revert all section settings to have their default values. Changed settings are not automatically saved; any settings that are changed will have a Restore Value icon button appear next to them.

Note that the Defaults button only affects settings for the visible section. Each section panel has its own Defaults button.

Some settings specify a Color Value which may take the form of an RGB triplet beginning with the crosshatch ('#') character, or a color name.

An RGB triplet is three hexadecimal values specifying the Red, Green, and Blue color component values preceded by a crosshatch ('#') character. Each component value must be in the range 0 (no intensity) to ff (255 decimal which is full intensity) and each value must have the same number of digits (so values with one digit must be padded with a leading 0 if there is any value with two digits).

A color name may be the name of a primitive color - "red", "green", "blue" - or the name of any primitive color combination - "cyan" is green and blue, "magenta" is red and blue, "yellow" is red and green, "white" is all three - in which each component will be at full intensity. "black" is all components at zero intensity. All World Wide Web color names are recognized. On host systems using a window manager based on the X11 windowing system all X11 color names are recognized.

Instead of specifying the Color Value directly a Color Selection Dialog may be used to interactively choose the value. Click the Select... button to bring up the dialog. The Color Selection Dialog provided by the host system will be used; the Graphs section shows an example for a Mac system. After a value has been selected from the dialog the Color Value field will be filled in with the corresponding specification.

The General Preferences control settings that apply to HiView as a whole.

When HiView starts up it can restore the geometry of its layout from the last time it was used.

When HiView starts up it can attempt restore the image source that was last opened.

Source data bands may be numbered by index - in which the lowest numbered band is 0 - or by count - in which the lowest numbered band is 1. This setting will affect all band numbering in all tools.

Index, or ordinal, numbering is used with ordered sets; the first element of the set has the number 0. All source data bands are ordered according to their logical occurrence in the source file, which may reflect a physical characteristic such as the position of the band data on a wavelength spectrum. Therefore HiView uses indexed band numbering by default.

Count numbering does not necessarily imply any inherent order in the elements being counted; the first element that happens to be selected from a group of elements is number 1. Nevertheless, count numbering is more familiar than index numbering. HiView will still maintain the inherent ordering of the source data bands when applying count numbering.

The HiView User's Guide documentation will be presented in a web browser when HiView Help is selected in the Help menu.

The location of the HiView User's Guide documentation may be a directory on the host's local filesystem or a URL for a directory on a remote HTTP server. If the directory entered does not contain the HiView_Users_Guide.html file an notice dialog will be displayed offering to use the location anyway (if the documentation is only temporarily unavailable) or to revert to the previous location value.

When the Find button is pressed HiView will try a built-in list of likely locations for the User's Guide; the list of locations is provided in the tooltip for the button. The first location where the documentation files are found is entered into the Location field.

The Sources section provides tools for managing the Source List contents. This includes allowing the user to change and remove Source Locations, reorder the contents of the list, as well change the maximum number of Source Locations that will be held in the list.

The Entries label displays the current number of Source Locations in the Source List. The Capacity setting controls the maximum number of entries that will be retained in the list.

The Source List contains Entries for the most recently opened Source Locations. The contents of the list may be modified as desired.

A Source Location entry may be selected by clicking on it. To select multiple adjacent entries, click on the first, hold down the Shift key, and click on the last. All entries between and including the two ends will be selected. To select multiple entries that are not adjacent press the Command (⌘) key on a Mac system, or the Ctrl key on other systems, while clicking on the entries to be selected.

To change the order of entries in the List, click and drag one or more entries to a new location.

Editing a Source Location entry can be initiated by selecting the entry and clicking the Edit button or by double-clicking the entry. At this point the Source Location may be edited by typing new location text and by using the text editing conventions of the host system. A pop-up menu for the field provides items and keyboard shortcuts for the various editing operations. Editing includes the ability to cut, copy, and paste to and from the entry. To enter the edited entry into the list press the Enter, or Return, key or click some other entry in the Source List. To cancel changes and restore the previous Source Location press the Escape key.

Clicking the Remove button will remove all selected entries from the list.

Whenever a change has been made to the contents of the Source List a Restore icon button will appear in the lower-right corner of the Source List pane. Clicking this button will restore the list to have the entries it contained before any changes were made.

The Rendering section provides settings that control how HiView renders images for display.

Scaling settings influence the possible image display scale factor values.

The initial scaling factor is used when an image is opened. For example, it might be convenient to have each opened image intially scaled to full (1.0) resolution. The scaling factor must be within the scaling range. As a special case, if the setting entered is zero - then the field will say "auto fit" - the initial scaling factor will be determined such that the entire image will fit within the Main Window Display Viewport. However, if the resulting scale factor is outside the scaling range the nearest range limit is used; e.g. if the image is very large it may not fit within a small Display Viewport area even at the minimum scaling factor.

Other than being a positive, non-zero value, there are no inherent limits to a scaling factor. However, limits need to be set to determine the range of scaling controls, which prevent using unreasonable scale factors that could produce unreasonable results. The default scaling factor limits have been chosen to limit descreasing the image display resolution to 0.01 - one one-hundredth the size of the full resolution image - and limit increasing the resolution to 10.0 - ten times full resolution. HiView enforces absolute limits of 0.001 and 100.0 for the scaling range.

Scaling conrols are provide to change the current scaling factor by a minor or major increment amount. For example, when the Scale Up item of the View Scale Image menu, or image display pop-up menu, is selected - or its shortcut key combination is used - the current scaling factor will be increased by the Major Increment. The default scaling increments - 0.01 and 0.1 - have been chosen to be appropriate under most circumstances. HiView enforces an absolute maximium of 1.0 for the scaling increments.

The Default Contrast Stretch applies Data Mapper Saturation Bounds using the Statistics Histogram percents specified by the settings here.

When an image region does not entirely fill the Display Viewport the viewport background is painted with the Background Color Value. The default black background was chosen because it is consistent with the color typically used for invalid image data pixels; i.e. source image data that is below the valid data Limit is typically a non-observation zero value from geometric image processing that leaves empty background areas in the resulting image, and these zero pixel values are usually mapped to zero display values that appear black on the screen. However, any other display color can be chosen if, for example, a clearer distinction between the image region and the Display Viewport background is desired.

HiView uses Display Tiles for managing the display of large JP2 files in the Display Viewport to help optimize image rendering time and user interface responsiveness. A display tile is a square area of the display; the Tile Size is the length of a side of the tile in display pixel units. The bigger the tile size, the fewer tiles have to be rendered, but the longer it takes to render each tile. Conversely, the smaller the tile size, the shorter the rendering time per tile, but the more tiles have to be rendered. The default Tile Size seems to strike a good balance for most systems.

When source data is being rendered and mapped to display data this is done in incremental chunks. The size of a chunck is the Tile Size width and the Incremental Lines height specified in display pixel units. When a chunk has been rendered and mapped it is painted in the Display Viewport. At this time, if the current display rendering has been canceled - either because the Activity Indicator has been clicked, or because display scrolling or scaling, or modified data mapping, has changed the image rendering requirements - the current rendering operation will not continue; instead any new rendering operation will begin. Interrupting a rendering operation can only be done when an incremental chunk has been completed. Thus the number of Incremental Lines, which is a hint to the rendering mechanism, affects user interface responsiveness. The default number of Incremental lines seems to achieve good user interface responsiveness for most systems without generating excessive overhead costs.

The JPIP section provides settings that control the interaction with a remote JPIP server.

When opening a Source Location specified as a URL, if it is an HTTP URL that contains a reference to a JP2 file HiView converts the HTTP URL to a JPIP URL request for the JP2 file. A key part of this conversion is replacing the hostname for the HTTP server with the hostname for the JPIP server. The HTTP-to-JPIP URL Hostname specifies the hostname that is to be used. The hostname may also be specified as an Internet Protocol (IP) address. If the HTTP-to-JPIP URL Hostname field is left empty then the hostname from the HTTP URL will be used.

The default hostname is the JPIP server at the HiRISE Operations Center that is suitable for use when dragging links for JP2 observation data products onto HiView from the HiRISE web site. However, any valid hostname for a JPIP server may be specified.

Along with the HTTP-to-JPIP URL Hostname, the Default Server Port is used in the conversion of an HTTP URL to a JPIP URL for a JP2 file. The appropriate port number, like the appropriate hostname, should be obtained from the system administrator for the site to be accessed. The HiView default value is suitable for use with the HiView default HTTP-to-JPIP URL Hostname. If the port number is set to zero the port number from the HTTP URL will be used.

If the JPIP server to be accessed requires the use of a proxy server system, provide the URL of the proxy system here. Information about a required proxy server should be obtained from the system administrator for the site to be accessed. If this field is empty no proxy system will be used. Normally none is required.

This is an experimental feature that is not currently in use.

The maximum time that HiView should wait, in seconds, while trying to connect to a JPIP server before giving up. The Maximum Wait Time applies to both JPIP and HTTP servers.

When opening a JP2 Source Location a low resolution version of the entire image is pre-rendered for use in filling in the Display Viewport until the requested source image data has been rendered. The amount of memory used for this background image is limited by the Maximum Source Image Area, measured in Megapixels (one Megapixel is 1048576 pixels). The source image will be rendered into the memory area provided using a scaling factor that will enable the entire image to fit. If the background image area is too large it can take too long to render the image; if it is too small the resolution of the image will be very coarse. The default value seems to provide a background image that usually renders in a reasonable amount of time and provides a background fill that looks satisfactory for most images.

The Graphs section provides settings to control the appearance and functioning of graphs used by the Statistics and Data Mapper tools.

When an element in the graph can be selected for interactive manipulation - such as the Data Mapper Functions - the Selection Sensitivity is used when determining if an element is close enough to the cursor position to be selected. The sensitivity value roughly corresponds to distance in screen pixel units. Larger values result in "sloppy" selection; smaller values provide a more "precise" selection.

The Canvas Color Value specifies the background color of the graph plotting area.

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