VISION Documentation		Last update: 05/07/98
Download documentation		2. VISION CONCEPT

2.1 "BitMap" images

A "bitmap" image is the computer description of a drawing or a picture. An image is made of a set of elementary points called PIXELS. An image is thus a rectangle x pixels wide and y pixels long, the total number of points being x*y (e.g., for a 320 wide pixels and 200 pixels long image, we have 320*200=64000 total pixels). The position of a pixel inside the image is given by its column number x and its line number y relative to the origin x=0 and y=0 located at the top left of the image. Each pixel can take a colour value according to the resolution of the image. For black and white, the point takes a value between two colours, black or white, while in True Colour, each pixel takes a colour value from more than sixteen millions. A pixel from a True Colour image is in fact described by its three components red, green and blue which allow, by mixing them, to obtain more colours than the human eyes can distinguish between.

2.2 The different resolutions

VISION allows to process images in all the resolutions offered by the ATARI ST and FALCON line, provided the image to be loaded has a number of colours less than the current screen resolution (e.g., on an Atari ST under a screen resolution of 320*200 in 16 colours, only 16, 4 and 2 colours images can be loaded). Another limitation comes from the computer memory. For instance, an image of 640*400 pixels in 16 colours takes 128 K, which is too much to be loaded on 520 ST, which memory is already partially occupied by VISION.

2.3 Work screen

VISION's work screen appears as soon as the program is launched. Every VISION command can be accessed from the menus, tools being also available from a movable window:

2.3.1 Menus organisation

Commands are grouped in 6 menus according to their function. All functions can be directly reached from a keyboard shortcut. This means the command can be reached from a combination of keystrokes. This combination is showed in the menu on the right of the corresponding function. ^S means the Control key and S must be pressed simultaneously, F1 corresponds to the F1 function key, whereas SF1 means the Shift key and the F1 key must be pressed simultaneously.

VISION Menu

	About vision ...	Gives access to the information dialog on the program version and the user name
	Accessory X	Allows at any moment to use a GEM accessory such as the Control Panel or a calculator

File Menu

	New ... (^N)	Creates a blank drawing page in a new window
	Open ... (^O)	Load an image from the disk with an automatic recognition of the file format
	Open as ...	Loads an image from the disk, specifying the file format
	Close (^W)	Deletes an image from memory
	Save (^S)	Saves the active image keeping its name and format
	Save as ... (^R)	Saves the active image after having specified its format and its name
	Batch convert ...	Allows an automatic conversion from any format to a given one
	Print ... (^P)	Allows to print the current image
	Quit (^Q)	Ends the use of VISION. A message warns the user if his work has not been saved

Edit menu

Tools1 Menu

Tools2 Menu

Options Menu

Extra Menu

2.3.2 The toolbox

The tools can be chosen in the Tools menus or in the Toolbox. The Toolbox is a window, which contains the main function of VISION as icons. This window can be moved, using the moving bar at the top, in order to put it at a convenient place on the work screen. A tool can be selected by a single click, even is the window is not active. The corresponding icon is then displayed in a lighter colour, and the cursor takes the shape of the tool.

A left click together with the Alternate key or a right click on a tool allows to configure its behaviour. This function is the same as the functions of the Options menu.

This last icon shows the size of the image visible in the window compared with the complete image. The white area corresponds to the complete image, while the black area corresponds to the visible part. If only the black area is visible, it means the complete image is visible. It is possible to move directly the window on the image, by dragging the black area to the desired place, keeping the left mouse button pressed.

2.3.3 The windows

The images appear in standard GEM windows. Clicking inside a window activates it. It then becomes the current working area, and is displayed on top of the other opened windows.

The moving bar allows to change the position of a window without changing its size. It contains the name of the file displayed, preceded by its path. C:\IMAGES\SERVAL.TIF means the window contains the image of the file SERVAL.TIF, which is on the drive C in the IMAGES folder.

When the * symbol is displayed before the file name, it means the modifications made on the screen have not been saved in the file. To do so, you only need to use the Save command in the File menu.

The information bar, when selected in the preferences in the Options menu, displays information related to the current tool, such as: position on the image, size of the object drawn, colour pointed.

A click on the closer erases the image from memory. If modifications have not been saved in the file, VISION asks whether the content of the image should be saved.

A configuration in the preferences in the options menu allows to quit VISION automatically when the last window is closed.

The maximum size button increases the size of the window to fill the screen, letting enough space to display the tools.

A second click on this button brings back the window to its initial size. If the image is not larger than the screen, the maximum size of the window is computed according to the size of the image.

The sliders have the same function as the Move image tool. Cursors correspond to the visible area on screen related to the moving area which corresponds to the size of the image. Moving the display area can be done either by clicking on the arrows, moving the cursor, or a click in the moving area. Since version 3.0c, you can also use the cursor keys to browse the image.

A maintained click on the size button allows to modify manually the size of the window.

Last, the iconify button, available under recent GEM, allows to reduce the window to a size of 80x80 pixels, with a reduced view of the image. A click on the same button restores the initial size. A right click on the iconified window displays a menu with the most used options

Last, a right click on the image displays a popup menu giving a quick access to the following functions:

Open, Maximise, Palette, Information, Save, Save as, Close, Run, LDV

The "Run" function allows to launch another program. If you are under a multi-tasking environment (MultiTOS, MagiC...) this program is launched in parrallel with VISION.

2.4 Real time zoom

Initially placed at the bottom right of the screen, this window displays constantly a zoom of the image or even of the graphic screen. Used together with the mouse arrow cursor, it allows to position precisely points on an image when using the tools. This window can also be configured, see configuration of the Real time Zoom. You can move this window to better suit your needs. To configure this window, just right click on it.

		VISION Documentation		Last update: 05/07/98
Download documentation		2. VISION CONCEPT