Measure - A tape measure for your screen

by Graham Crow


Measure simulates a tape measure and provides an intuitive means of measuring distances on the screen by dragging a 'rubber band'. You can choose to measure relative to either the screen origin or a window's work origin, and the units may be OS units, pixels, or text characters. To improve accuracy, the cursor keys will move the pointer and a magnifying glass is available. Measure requires RISC OS 3.1 or later.

There are many reasons why you might want to measure distances on the screen; for example:

 - to check that icon sizes and spacing conform to the Style
   Guide
 - to position an icon relative to a window's work area
 - to find the visible area width of a window
 - to count the number of characters in a row of text
 - to count the number of lines in a text window
 - to check the resolution of the current mode


Loading Measure
Install Measure in the usual way by double-clicking on the !Measure icon in a directory display or by clicking on its icon in the Risc User Menu program. This places its icon on the icon bar and opens the display window.


The display window
The window provides space to show the x and y coordinates at the start and end of the measurement, together with the lengths. The current mode is shown (though this will be meaningless on a Risc PC), and alongside it, a pop-up menu icon. There is also a magnifying glass icon.

Clicking on the toggle size icon opens the display window to its full extent revealing three sets of radio icons. The first determines the point of origin, relative to which the measurement is made: either the screen or the work area of the window under the pointer. The second controls the unit of measurement: either OS graphic units (the units used for simple graphics plotting), pixels (the smallest individually alterable unit of the display), or text characters. Note that text character sizes are those that are plotted by the operating system when outside the desktop. In certain modes the desktop System font will be exactly this size, but in other modes its height will be twice that of measured characters. The final set of radio icons determines whether the pointer should be confined horizontally, vertically or neither when taking measurements. The selection is reflected in the window title.

The resolution for the current mode may be seen by clicking Select or Menu on the pop-up menu icon. This opens a window giving the x and y coordinates for all three types of unit together with the dimensions of a pixel and text character in OS units.


Making a measurement
First make your choice of origin and unit, and decide whether to confine the pointer.

Then position the pointer on the spot from which you want the measurement to start. To make this easier you can use the cursor keys to move the pointer by the smallest amount possible (holding down Shift at the same time speeds up the movement). You may also want to use the magnifying glass which can be invoked by clicking on its icon or by pressing Tab.

When the pointer is in the required position, press either of the Alt keys. This opens a tiny window at the pointer position and confines the pointer to it. If the magnifying glass is turned on, you may have to hold down Alt or press it twice. The magnifying glass is then turned off.
     
To make your measurement, drag the 'rubber band' to the desired position and notice that, as you drag, the coordinates and lengths are continuously updated in the display window. Note also that the drag is confined to the screen or work area boundary, as appropriate (this is useful for checking a window's work area, part of which may lie outside the screen area). As soon as you end the drag, the rubber band and tiny window disappear, leaving the required data in the window. Note that you can also release the pointer by clicking with Select or Adjust, or by pressing Escape.

If you wish, you can bring up the magnifying glass while dragging by pressing Tab. This will pause the rubber band, but when you press Escape (while still dragging) the rubber band extends to the pointer and the magnifier disappears.         


The icon bar menu
As well as the usual Info and Quit, there is a Help option which brings up a window to remind you of the relevant buttons and keys. If you want to leave this window open, click on Help. To close it again later, reopen the menu and move across the Help menu option's submenu pointer. This will reopen the window by the menu, but it will close again when the menu closes.

Clicking on the window's Close icon, or clicking Adjust on the icon bar icon, closes the window and 'locks' the tape measure so that it no longer processes null reason codes from the Wimp. This is useful if the keys used by Measure are interfering with their function in another Application, and it could also speed up the desktop. Clicking with Select reverses the effect and opens the window. 

 Copyright RISC User 1994
