Snowflake Online's Features

Basic Operation

At the most basic level, the user clicks on the picture to indicate where the "active" control point should be moved, and an image is returned reflecting the shape of the curve with the control point in the indicated location. (The rules the computer uses to draw these curves is described in "How Snowflake Works".)

Settings and Options

Active Point

The "Active Point" popup menu indicates which point is to be moved when the user clicks on the image (clicking on the image is one way to submit (send off for processing) the form). Whichever point is indicated in the menu will move to the location that the user clicks. (If the Snap To Grid option is checked, the active point will move to the grid point nearest the location of the user's click.)

Iterations

The "Iterations" popup sets the number of iterations that will be used the next time the picture is redrawn. The two buttons "Down One" and "Up One" cause the picture to be redrawn with one less (or more, respectively) iteration than the current picture. (If you don't know what "iterations" have to do with anything, you should probably read "How Snowflake Works".)

Redraw

This button causes the picture to be redrawn with the current settings. The "Number of Points" popup menu is ignored, and upon return that menu will reflect the current number of points. To change the number of points, the user must set the desired number of points with the "Number of Points" popup menu, and then submit the form with the "Reset | Change number of points" button.

The "Redraw" button is useful at any time when the user wants to change a setting and redraw the picture without changing the location of the control points. For example, one might wish to change the number of iterations with the "Iterations" popup menu, or change the shape or visibility of the grid, etc.

Number of Points

The "number of points" popup always starts out displaying the current number of points--changing this setting will only have effect if you also push the "Reset | Change number of points" button.

Reset | Change Number of Points

This button has two basic functions. First, it is a simple way to quickly move all the control points back to a horizontal line in the center of the picture. Second, it will change the number of control points to that number indicated in the "Number of Points" popup menu.

Plain/Grid Background (radio buttons)

If "Plain Background" is selected, the curve is drawn on a white background. If "Grid Background" is selected, the curve is drawn over a light gray grid, which is designed to help the user line points up, etc. In particular, this is the grid that the control points "snap" to when "Snap To Grid" is checked.

Note:The grid is "there", whether is is visible or not--if you have "Snap To Grid" checked, it will work even if you have "Plain Background" selected.

Grid Size (popup menu)

Allows the user to select between three different sizes of grid. The smallest grid leaves eight pixels between centers of adjacent grid points, the largest leaves 32, and the middle 16.

Grid Shape (popup menu)

Allows the user to select between a square grid (the grid points are at the corners of squares) or triangular grid (the grid points are at the corners of equilateral triangles).

Snap to Grid (checkbox)

When checked, the control points will only move to the grid points (it works whether the grid is visible or not). This affects only the control points which are clicked on while the option is checked, so you can turn it on, move a single point to a desired grid location, and then turn it off and move the other points wherever you like.

Show Iteration Zero

Draws the zeroth iteration in green. This, if used in conjunction with "Show Iteration One", shows the entire "drawing rule" (see "How Snowflake Works" if "drawing rule" means nothing to you.)

Show Iteration One

Draws the first iteration in green. This, if used in conjunction with "Show Iteration Zero", shows the entire "drawing rule" (see "How Snowflake Works" if "drawing rule" means nothing to you.)

Dehanced for Internet Explorer and Mosaic

This is automatically "checked" (that is, the checkbox is ignored, and treated as if it's checked no matter what the user does) if you are using Internet Explorer or Mosaic. These browsers do not send the correct coordinates when the submit image is in a table. If you find that the points you are clicking seem to not match the output, you may want to try checking this box and seeing if that fixes things.