Use the select control located on the drag-n-drop toolbar to assign a region number to the area you plan on hiding on the map. Next, make sure the check box labeled "Place Fog" is checked. Now click on the map and you should see a small black rectangular fog appear. Hold down either the "Ctrl" key or the "Shift" key, then click and drag on the fog to resize it. You can also click and drag the fog to move it any place on the map. Repeat the process until you have covered everything you want to within the region. (Performance Tip: Try to be efficient by placing as few fogs associated with each region as possible.)
To hide other areas on the map, select a different region with the select control and repeat the process described above. Associating the fog images with different regions allows you to reveal portions of your map based on region.
Hold the mouse cursor over the blackend area of the map you want to reveal. You should see a tool-tip display showing the region number. Select this region with the select control, then click on the "Uncover Region" button. If you wish to re-hide this region click on the "Hide Region" button.
Click in the textbox directly to the left of the "Load" button on the toolbar. Type the filename and file extension of the map you wish to load (ex. UltimateMap.jpg). Any maps you wish to load must be located in the "Maps" folder located in the same directory as Map View.html. Then, click inside the textbox located directly below the one you typed the map name into. This text box controls the size the map will be loaded at. Type a whole number representing the percentage of the original maps size that the map will be displayed at. For instance, a value of "100" in this textbox then clicking the "Load" button will display a map at its original size. Typing a value of "20" will display a map scaled at 20% of the original maps size.
You can only load maps with an image file type that typical internet browsers are capable of displaying. Also, there may be performance concerns when loading large maps or large maps sized to percentages other than 100.
For your convenience, the toolbar can be move to any position on the screen. Right-clicking the mouse moves the toolbar to the screen position of the mouse cursor. This is useful when navigating around large maps and loosing track of the toolbar. Clicking the button labeled "Hide Tools" causes the toolbar to disappear. Right-clicking the screen causes the toolbar to reappear at the current mouse cursor location.
There is more functionality on the way in future updates. Hopefully Including...
Ideally I had envisioned this application to be used at the game table. A single large monitor, projector, or line out to a TV which all players and the GM could see. The GMs job is to load up the maps (with the regions pre-hidden) and uncover the hidden regions for the players. A wireless mouse would be handed around the table on each players turn to move their token on the map and declare their actions. But this is just me dreaming...