The image size window
This dialogue allows the
calculation of image size in mm and inch from pixel size at varying
dpi (dots per inch) or scale. You also have the option of specifying
an aspect ratio. The dialogue should be self explanatory.
The three radio buttons Pixels, mm and inch allow you to choose the 'input' units. The values are then typed into the corresponding Width and Height fields. Pressing <return> or clicking on the Calculate button then calculates the other values.
The Menu buttons to the right hand of the Width and Height fields enable the quick entry of some common image sizes. In this case the calculation is done immediately a set of values is chosen from the menu.
The scaling can be done using either dpi or %, selected by means of two radio buttons. Common values can be entered from the pop-up menus, other values can be typed into the field. You need to press <return> or click on the Calculate button to obtain the result. Remember that, under RISC OS, the standard 100% scale for the screen display is assumed to be at a pixel density of 90 dpi.
You also have the option to specify the aspect ratio, by ticking the appropriate button. The Width/Height ratio will then be fixed. When <return> is pressed, or the Calculate button is pressed, the Width field is tested, and if a value is found, the calculation is done and the Height field is filled in before the conversions are done. If you enter a width/height combination from the pop-up menu, the height value will be ignored, but will be calculated from the width value.
If the Width field is blank, then the Height field is read, and the Width filled in using the fixed aspect ratio before the rest of the calculation is done.
At the foot of the dialogue are the two action buttons Close, which simply hides the dialogue, and Calculate, which forces a new set of values to be calculated.