Information Technology

aViewer ImageViewer

Warning: At this time the image viewer (aViewer) does not work with Safari or Chrome.

Configuration of aViewer is controlled by the aViewerConfig object passed to aMapApp3 at creation time.

The aViewer is an image viewer object contained within the aMapApp3.  When an image thumbnail is double clicked in the image display tab of the location display, the aViewer is launched.  At start up it will take up most of the screen, but it can be resized or moved as needed.  At the moment, aViewer can not be used outside of aMapApp3 but it may be spun off if there is interest.

aViewer

aViewer supports a mouse drag function to move the image around in the display area.  It also supports a mouse click-zoom capability that allows the user to click on any spot in the image the image will zoom in the next larger size and recenter the image on point that the user clicked. Other than these two abilities, control of aViewer is through the toolbar at the top.

Navigation options
  • Zoom in - Increase the magnification to the next level.  This will double the size of the image until it reaches the original resolution.  After than the the image only increases by 25%.  Above the original resolution, image quality drops rapidly.
  • Zoom out - Decreases the magnification to the next lower level.  If the image is at or below the original resolution, the image size is cut in half.  If it is above the original size it is cut by 20%.  The image will not zoom out if both the height and width would be less than 300 pixels.
  • Fit Screen - Resize the image to fit the available display area.  Either the width or the height will precisely fit into the display.  Zooming in our out after this option will cause the image to be displayed at one of the basic zoom levels - which are factors of the original resolution - rather than a size determined by what fit into the screen.  This is the default setting for initial display of an image.
  • Full Size - Display the image in the original resolution.
Slide Show options
  • Next - Go to the next file for the location.  Non-image files will be automatically skipped.
  • Previous - Go to the previous file for the location.  Non-image files will be skipped.
  • Go To... - The Go To pull-down menu shows a list of images and their names.  The user can select which image they want to be displayed.

    gotoaViewer
  • Tiles - The tiles pull-down menu allows the user to quickly bring up a number of aViewer windows. The most common possible combinations are provided, plus a custom arrangement can be configured so, for instance, if your working with Chinese hanging scrolls, you could create a display of one row and eight columns.  We have gotten 48 windows up at one time but it was slow and the window size is very small.  Attempting 96 windows failed.  The tiles option will use the entire display area minus any holes created by the arrangement, i.e. eight displays appear as two rows of three and one row of two with the ninth position empty.  Initially every display will show the same image, but this can be changed and, once on the screen, the individual windows can be move and resized as needed.  If you increase or decrease the number of tiles, existing windows will be resized, but the contents will not change.

    tileaViewer

    With the predefined arrangements, the number of columns equals or is one greater than the number of rows.


    New tiles are initially filled with the same image that was first selected to open the aViewer.  If a tile is openned, the image changed, the tile closed and reopened, it will still contain the last image displayed in that tiles. 

    There are two know issues with tiles.  First, if the window is too small, you wouldn't be able to see all the options.  There should be a double arrow indicator on the left to get to the rest of the options, but this only appears to work once.  If you choose any option off of the display, the double arrows go away.  The second issue with tiles is that occasionally they don't work.  We don't know what causes this and so far, shutting down aViewer and restarting it solves the problem. Safari and Chrome appears particularly vulnerable.
Display Options
  • Background - The Background option allows a user to change the color of the area that surrounds the image.  The default is black and is one of the few things in aMapApp3 that can't be configured. Our example below show a blue background with a bit of the image off to the left.
    backgroundaViewer
  • Show/Hide Details - The Show/Hide Details option (only one is available at a time) toggles a window containing the description/analysis text for the image.  By default, details are hidden at start up but this can be configured as can the location when the detail window should appear.
    detailsaViewer