Presentation Graphics (basics)

Annotation Window

General tab

GeneralAnnotation.png


Note that 'No Annotations' is not a toggle.

It turns off annotations altogether. To undo this action, you must use the 'Reset' button. However, this also resets settings to their default, so changes made previously may be lost if not saved via the 'Make default' button. Alternatively, you can turn settings back on individually.

Colors tab

ColorsAnnotation.png


Allows changing foreground and background colors, as well as applying special styles to the background like Gradient and Image. Gradient background interpolates between two colors based on pattern chosen (Radial, top-to-bottom, etc). Image background allows browsing the file system for the desired image, and selecting repeat rates in x and y if desired. Image Sphere can be used for 3D plots, and will map the image to a sphere that will track with the camera as it is moved, so the background appears to move as well.

2D tab

2D General.png
  • Show axes: toggles the display of 2D axes
  • Auto scale label values: turning this off allows you to modify the scaling of axis labels that VisIt may have applied. Can be useful to decrease or increase the signficant digits displayed. (See individual axis tab for changing the scaling.)
  • Auto set tick marks: turning this off allows you to specify a different minimum and maximum displayed, and to change the spacing between major (with label) and minor tick marks. (See individual axis tab for changing these values).
  • Tick mark locations:
    • Outside (default): tick marks are displayed pointing outward form the bounding box.
    • Inside: tick marks displayed pointing into the plot.
    • Both: displays both inward and outward facing tick marks.
  • Show tick marks: controls which edges of the bounding box will display minor tick marks and/or gridlines.
    • Bottom-left (default)
    • Bottom
    • Left
    • Both
    • Off: Note: must also turn off labels on individual axis tabs in order to remove major-tick marks and their associated labels.
  • Line width: controls width of lines for tick marks, bounding box and grid lines.



3D tab

3D General.png
  • Show axes: toggles the display of 3D axes
  • Show triad: toggles the display of the Triad in the lower left corner of the screen that aids in understanding the orientation of the plot in 3D space.
  • Show bounding box: toggles the display of the bounding box.
  • Auto scale label values: (same as for 2D)
  • Auto set tick marks: (same as for 2D)
  • Tick mark locations: (same as for 2D)
  • Axis type: controls which edges of the bounding box will display minor tick marks and/or gridlines. All but the 'static' options change position with camera movement.
    • Closest triad (default): The three edges closest to the camera that represent each axis.
    • Furthest triad: The three edges furthest from the camera that represent each axis.
    • Outside edges:
    • Static triad: The edges emanating from where the minimums of each axis meet.
    • Static edges: All edges.
  • Line width: controls width of lines for tick marks, bounding box and grid lines.
  • Set bounding box location manually: Turning this on allows the specification of the bounding box location, which may be useful when animating through time and the spatial extents change over time.



Axis controls

AxisControls.png

Part of 2D and 3D tabs, there is one for each axis, and the controls are the same for all.

  • Title: toggle to control display of axis title, turning it off disables other Title controls.
    • Custom title toggle to enable entering a custom title.
    • Custom units toggle to enable entering custom units.
    • Font controls: name, scale, bold, italic
    • Use foreground color: toggle to enable specifying a custom color to use for the title.
  • Labels:
    • Scaling: enabled when Auto scale labels on General tab is turned off.
    • Font controls: (same as for Title).
  • Tick marks: enabled when Auto set ticks on General tab is turned off.
    • Major minimum: minimum value to use for major tick marks.
    • Major maximum: maximum value to use for major tick marks.
    • Minor spacing: spacing to use between minor tick marks.
    • Major spacing: spacing to use between major tick marks.
  • Show grid: toggles display of grid lines along major-tick values.


Objects

Controls for creating objects that add more information, or point out interesting aspects of the plot. Types of objects that can be created from this window: 2D text, 3D text, Time slider, 2D Lines, Images. To create a new object, select one of the buttons in the the Create new' pane. A window will pop up requesting a name for the object (can be helpful if you later plan to manipulate the object via the python interface). The Annotation objects pane will display all available objects. Select one to activate its controls, or to use its hide/show toggle, or delete it from the list.


Legend Controls

Legends are automatically created when a Plot is added, and can be manipulated from this window.

Position
Legend-Position.png
  • Let VisIt manage legend position: when turned off, enables the manual positioning controls.
  • Legend position: x y in normalized screen space, with values between 0 and 1, (0,0) being the lower left corner. The down arrow button is a positioner tool, allowing a coarse-grained visual positioning.
  • X-scale and Y-scale: allows modifing the legend size in x/y (width/height) individually.
  • Orientation:
    • Vertical, Text on Right (default)
    • Vertical, Text on Left
    • Horizontal, Text on Top
    • Horizontal, Text on Bottom


Tick Marks
Legend-TickMarks.png
  • Let VisIt determine tick labels: when turned off, allows for modification of tick values and labels associated with the values.
  • Num Ticks: Change the number of ticks/values displayed (default is 5)
  • Inclusive of min/max: Toggle to specify whether or not the tick marks/values include the minimum and maximum data values.
  • Draw: Controls what is displayed next to the tick marks.
    • Values (default)
    • Labels
    • Values and Labels
    • None (no labels, no values, no tick marks)
  • Specify tick values and labels: Allows for changing the values displayed and addition of textual labels. This can be useful if you want varying spacing between tick marks. Values entered that do not fall within the data range will be ignored. Re-toggling the Let VisIt determine tick labels will reset the values.
  • Add tick value: adds a new blank entry to the bottom of the table.
  • Delete selected value: removes the selected entry from the table


Appearance
Legend-Appearance.png
  • Bounding box: toggles display of a bounding box around the legend, and when on enables changing the color and opacity of the bounding box.
  • Draw title: toggle display of the legend title
  • Draw min/max: toggles display of the min/max data values.
  • Use foreground color: toggles the ability to change the text color from foreground to custom.
  • Font controls: height, family, bold, italic
  • Number format: controls how values are displayed


"Example of a modified legend"


Text controls

Text-2Da.png

2D text that will not be obscured by plots. Can be useful for adding titles to a screen shot, or pointing out interesting features (in conjunction with lines/arrows). Multiple text objects can be created for display in a single window.

  • Lower left: The lower left corner of the text, specified as (x y) in normalized screen space, with values between 0 and 1, (0,0) being the lower left corner. The down arrow button is a positioner tool, allowing a coarse-grained visual positioning.
  • Height: allows modifying the text height.
  • Text: for entering the contents of the text to be displayed
  • Use foreground color: toggles ability to change color of the text.
  • Font controls: family, bold, italic, shadow
  • Visible: toggles the visibility of the selected text object. (Can also be controlled via the Hide/Show toggle)


2D Line controls

2D Line.png

Adds a 2D line that will not be obscured by plots. Can have optional arrowheads at begin or end points.

  • Start: The starting position for the line, specified as (x y) in normalized screen space, with values between 0 and 1.
  • End: The ending position for the line.
  • Width: line width, valid values between 1 and 10.
  • Line color:
  • Begin arrow: Arrowhead at start position.
    • None (default, no arrow)
    • Line (arrow drawn as lines)
    • Solid arrow drawn as solid triangle
  • End arrow: Arrowhead at end position.
    • None (default, no arrow)
    • Line (arrow drawn as lines)
    • Solid arrow drawn as solid triangle


Time slider controls

Annotation TimeSlider.png

Visual aid for representing current time in an animation.

  • Lower left: The lower left corner of the text, specified as (x y) in normalized screen space, with values between 0 and 1, (0,0) being the lower left corner. The down arrow button is a positioner tool, allowing a coarse-grained visual positioning.
  • Width: allows modifying the text width (as a percentage of the screen width)
  • Height: allows modifying the text height (as a percentage of the screen height)
  • Text label: optional text. Using $time will display current time, $cycle will display current cycle. Both can be used in conjunction with other text.
  • Start color: color to be displayed from starting time position to current time position on the slider.
  • End color: color to be displayed fro the current time position to the last time position on the slid
  • Use foreground color: toggles ability to change color of the text.
  • Font controls: family, bold, italic, shadow
  • Time source:
    • All frames (default)
    • Frames for plot
    • States for plot
  • Visible: toggles the visibility of the selected text object. (Can also be controlled via the Hide/Show toggle)
  • Rounded: toggles the endcaps rounded stated
  • Shaded: toggles the shading of the slider (toggled on, provides visual dimensionality)


Image controls

Annotation Image.png

Add an image to the window.

  • Image source: file system location of image. Press the '..' button to open a file browser window.
  • Lower left: position of the lower left corner of the image
  • Width: width as a percentage of full image size.
  • Height: height as a percentage of full image size.
  • Lock aspect: when toggled force width and height aspect ratio to remain the same. Changing either width or height will also change the other.


Saving Windows

test

VisIt offers a variety of ways to save results to files. Here we will talk about VisIt's Save Window features.

Its important to understand the difference between a Save Window operation in VisIt and, for example, an Export Database operation. The main distinction is that the Save Window operation is aimed at saving whatever is currently being displayed in VisIt's viewer window(s) while an Export Database operation is aimed at saving the (typically 3D) result of some plot pipeline; the mesh together with selected variables on the mesh. However, this distinction is sometimes muddied because VisIt's Save Window feature offers options to save either a 2D image raster or (some of) the 3D geometry that is being rendered in the window.

The Save Window Options window is depicted here.

Filename

This allows you to specify the base filename that VisIt will save an image to. Note that VisIt will automatically add the file format extension.

The default location into which VisIt will save windows depends on how VisIt was started and on what platform you are running.

Starting from an Icon

When you start VisIt by double clicking on an icon, the default directory into which windows are saved is

  • Windows: My Documents
  • OS X: $HOME
  • Linux: $HOME

Starting from a Shell

When you start VisIt from inside of some shell by typing a command at the shell prompt, the default directory into which windows are saved is the current working directory of the shell at the time VisIt was launched.

Family Check Box

With this check box enabled, VisIt will automatically append a 4 digit (%04d) sequence number to the filename before automatically adding the format extension. So, for example, if you specify foo for the filename, and png is the selected format, VisIt would generate the filename foo0000.png.

With this option enabled, VisIt will never overwrite an existing file. Before generating the sequence number, VisIt examines the destination directory for any pre-existing files with the same base name and 4 digit sequence number as the intended file. From among any matching files, Visit then determines a next sequence number to use to name the current file to avoid overwriting any existing files. If you have files foo0000.png, foo0001.png, foo0004.png (note that 0002 and 0003 are missing) already in the current directory and perform several Save Window operations. Visit will generate the names foo0002.png, foo0003.png and foo0005.png. Finally, VisIt will issue a warning message if it winds up skipping sequence numbers to avoid overwrites.

File Formats

VisIt offers 3 different kinds of Save Window file formats; Curve, Image Raster and 3D formats. We only briefly describe these formats below. For more information regarding various file formats mentioned here, see this page.

Curve Formats

VisIt offers these Curve formats: curve, ultra.

Curve formats are for saving the actual numerical X-Y pair values that define the curve(s) being displayed in a given window. Curve formats can be used to save the contents windows that are displaying only curves and no other 2D or 3D geometry. If you have a window with a curve overlayed on some 2D geometry, then the window contains a mixture of curves and 2D objects and its contents cannot be saved using a Curve format.

Curve formats are often useful for getting X-Y values out of VisIt and into some 3rd party tools such as Microsoft Excel or PowerPoint.

Image Raster Formats

VisIt offers these Image raster format: png, jpeg, bmp, ppm, rgb, tiff and ps (postscript).

In our empirical experience in almost all cases, the png format provides the highest (lossless) compression combined with the best quality. If for some reason the png format is not suitable for your workflow, a good second option is the tiff format. In addition, there are a number of 3rd party tools for converting between image formats such as Adobe Photoshop, Gimp and ImageMagick (which is available on Windows, OS X and Linux).

Finally, be aware that although the postscript format is most often used for vector graphics, in VisIt Save Window operations, it is used only in raster mode.

3D Formats

VisIt offers these 3D formats: vtk, stl, obj, ply and pov.

With 3D Save Window operations, in most cases, VisIt saves only the geometry of the object being displayed in the window and not any other attributes such as color. However, the vtk format will save these other attributes as additional variables on the 3D mesh object.

Next, often the geometry that is saved is tessellated differently than the original geometry displayed in VisIt's window(s). The vtk and ply formats seem to do the best job at faithfully representing the original geometry.

By default, all of these 3D formats are ascii. So, the file sizes can be a bit on the larger side.

We could include vtk as a curve format here as well. vtk is really best suited as a 3D format. However, in rare cases, vtk can be gainfully employed for curve data in 3rd party tool workflows as well.

Format Specific Options

Some formats offer additional options. These options are either disabled (e.g. grayed out) or enabled depending on the selected format.

Compression type menu

Some formats offer multiple ways to compress the files. Be aware that most image compression algorithms are lossy meaning they do not faithfully represent the original data. The tiff format offers both lossy and lossless compression techniques. The png format offers only lossless compression and so does not provide any controls for it.

Quality Slider

Formats that support lossy compression, sometimes also provide a quality control. The higher the quality (e.g. moving the Quality slider control further to the right) the larger the resulting file (e.g. less compression).

Binary Check Box

A majority of the 3D formats offer the option to write binary instead of ascii data. By default, the 3D formats write ascii data. In empirical testing, binary formatted files are 2-2.5x smaller than ascii formatted files. The binary check box, when it is enabled, can be used to turn on binary output.

Force Parallel Merge Check Box

Saved Image Resolution and Aspect Ratio

Example of oblong viewer window with GUI widgets highlighted in red

VisIt's viewer, where images are rendered, contains two menu bars and widgets which are part of the viewer GUI. These GUI objects share some of the the same vertical window real estate as the data objects VisIt is rendering. However, VisIt's save window feature saves only the data object part of the viewer window. This can create some confusion when trying to set a specific size and aspect ratio of saved images.

The Width and Height text boxes alone do not determine the final size of the saved image. The selected aspect ratio setting combined with the width and height settings determines the final size of the saved image. Below we describe the various aspect ratio settings.

Screen Ratio

When Screen ratio is selected, only the width text box value is used. The height text box is disabled and its value ignored. VisIt saves an image that has the specified width and a height such that it matches the aspect ratio of the image as it is currently displayed on the screen in the viewer window. Depending on the value you specify for width, the resulting saved image may be larger or smaller than the currently displayed viewer image.

1:1 Aspect Ratio

When 1:1 aspect ratio is selected, only the width text box value is used. The height text box is disabled and its value ignored. VisIt saves a square image that has the specified width and equal height.

No Resolution Constraint Ratio

When No resolution constraint is selected, VisIt uses both the width and height text box values. VisIt saves an image whose size is the specified width and height.

A Comparison of Different Aspect Ratio Constraints

Only the Screen Ratio method is assured of producing a faithful representation of what is currently being displayed in the viewer window. Both the 1:1 aspect ratio and No resolution constraint methods can wind up changing the aspect ratio such that the saved image may be dramatically different from that which is currently displayed in the viewer window. A common outcome with these two later approaches is that they can wind up causing annotations and annotation objects relative positions to change dramatically in the saved image.

Here we compare the results of a Screen ratio save and a 1:1 aspect ratio save from the original VisIt window configuration shown above. Note that the red line annotation object relative size and position is significantly different between the two saved images.

Screen capture

If you check the Screen capture box, you will save images that are a verbatim representation of what you see on the screen. However, you are also limited in that the resulting image size(s) are only those that can fit into windows displayed on your screen. Often, such images are not high enough resolution for publication or other purposes.

Note that as of this writing, VisIt's Rendering->Anti-aliasing setting works *only* in screen capture saves. If you do non-screen capture saves, antialiasing is ignored. However, with non-screen saves, its possible to achieve anti-aliasing by saving at super-resolution and then using any of a number of common image processing tools (Gimp, Photoshop, ImageMagick) to resize and down-sample to the desired resolution.

Saving stereo pairs

The Stereo check box allows you to save stereo pairs. It will save two image files one for the left and right eye. Each image file will be saved according to the aspect ratio and size selections you specify. You may want to turn off the Family check box for stereo pair saves because earlier versions of VisIt neglect to identify the left and right images when the Family check box is enabled.

Multi-Window Saves

VisIt provides two convenient ways to save multiple windows. One is a basic Save Tiled method. The other is an Advanced Multi-Window save method.

Save Tiled

In a tiled save, VisIt will do what amounts to a 1:1 aspect ratio save for each window. It will then take each of these individual window results and paste them into a larger tiled image. You specify the width of the tiled image and from that width, VisIt decides how to size each image tile such that all the window tiles fill the combined resulting saved image.

From a selected layout

If you have selected a specific layout from Windows->Layouts, then VisIt will save a tiled image that matches the layout you originally selected. It does not matter if you have moved and/or resized windows from how they were originally layed out by VisIt. VisIt does not queue off the current window sizes or positions when doing a tiled save from a selected layout. It uses the original layout to determine the windows relative positions and then sizes each image such that the resulting tiles fill the specified width and height of the saved image. In addition, it will save each window's contents in the layout regardless of whether the window is empty/blank at the time you did the save.

With no layout selected

However, if you have not selected a window layout, then VisIt has no layout clue to suggest how those windows should be tiled into a combined tiled image save. In that case, a tiled save takes all the windows which currently display some plots (e.g. are not blank windows) and orders them in order of increasing window id (the number you can see in the title bar for the windows). In that case, VisIt will create as many rows of tiles as the square root of number of the non-blank windows being saved. If you have 3 or fewer (non-blank) windows, VisIt will tile them into 1 row. If you have 4 or more but less than 9 windows, VisIt will tile them into 2 rows. If you have 9 windows but less than 16, VisIt will tile them into 3 rows, etc. It then tiles the windows to be saved in increasing window id, row-by-row starting at the top. Ordering of images in the tiled result is based on window ids and not on their left-to-right-top-to-bottom appearance on the screen.

For example, for two windows to be saved to an image width of 1024, VisIt will save one row of two tiles, each tile is 512x512. For 3 windows, VisIt would save to a single row of tiles, each tile 341x341 (3x341=1023) while for 4 windows, it will save to 2 rows of tiles where each tile is 512x512.

A couple of examples of tiled saves are illustrated below.

Here we show a screen shot of the actual VisIt window configuration on the screen and then the resulting tiled saved images.

In the first tiled save, VisIt uses 2 rows of tiles (because there are more than 3 windows with non-blank contents and less than 9). Note the difference in the histogram plot (brown bar chart) position between how the windows appear on the screen and in the resulting tiled saved image. This is due to the fact that image tiles are ordered according to window id and not their relative positions on the screen.

In the second tiled save, note that only 3 tiles are saved. Since the number is 3 or less, VisIt uses only one row of tiles. The reason only 3 tiles are saved is that one of the windows is blank (contains no plots). So, that window is excluded from the save.

In many cases a Standard tiled save is sufficient. However, sometimes users require more control over size and position of windows in the resulting combined output. That is what the Advanced Multi-Window Save tab is for.

Advanced Multi-Window Save

Advanced Multi-Window Save Controls

First, be sure to check the Do Advanced Multi-Window Save box.

In the Advanced Multi-Window Save controls do everything manually. For each window, whether or not the window is currently blank, you need to indicate to VisIt the following information

  • Whether to include or omit the window
  • Width and Height of space the window will occupy in the combined result.
  • X and Y offsets of the lower-left corner of the window relative to a 0,0 origin in the lower-left corner of the combined result
  • Which layer the window should be put into and the transparency of the window in that layer. layers are stacked up away from the eye with layer 1 closest to the eye.
Advanced Multi-Window Save Example

In the example at right, 4 windows are saved to a 1024x1024 image. 3 Windows are saved in layer 1 and a second window is saved in layer 2. The following paramters were used

  • Window 1: Omit=Unchecked, Width=1024, Height=512, X Position = 0, Y Position=0, Transparency=50%, Layer=1
  • Window 2: Omit=Unchecked, Width=512, Height=512, X Position=0, Y Position=512, Transparency=0%, Layer=1
  • Window 3: Omit=Unchecked, Width=512, Height=512, X Position=512, Y Position=512, Transparency=0%, Layer=1
  • Window 4: Omit=Unchecked, Width=512, Height=512, X Position=256, Y Position=256, Transparency=0%, Layer=2