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Matrix is a class used for creating groups of Cells that work together in various ways. It includes methods for arranging its Cells in rows and columns, either with or without space between them. The only restriction is that all Cells must be the same size. Cells in the Matrix are numbered by row and columns, each starting with 0; for example, the top left Cell would be at (0, 0), and the Cell that's second down and third across would be at (1, 2). A Matrix can have many Cells of different classes, but usually uses only one type of Cell. A Matrix can be set up to create new Cells by copying a prototype Cell, or by allocating and initializing instances of a specific Cell class.
A Matrix adds to Control's target/action paradigm by allowing a separate target and action for each of its Cells in addition to its own, and also by having an action that gets sent when the user double-clicks a Cell, and which is sent in addition to the single-click action. If a Cell doesn't have an action, the Matrix sends its own action to its own target. If a Cell doesn't have a target, the Matrix sends the Cell's action to its own target. The double-click action of a Matrix is always sent to the target of the Matrix.
Since the user might press the mouse button anywhere in the Matrix, and then drag the mouse around, Matrix offers four "selection modes" which determine how Cells behave when the Matrix is tracking the mouse:
NX_TRACKMODE is the most basic mode of operation. All that happens in this mode is that the Cells are asked to track the mouse with trackMouse:inRect:ofView: whenever the mouse is inside their bounds. No highlighting is performed. An example of this mode might be a "graphic equalizer" Matrix of sliders. Moving the mouse around causes the sliders to move under the mouse.
NX_HIGHLIGHTMODE is a modification of TRACKMODE. In this mode, a Cell is highlighted before it is asked to track the mouse, then unhighlighted when it is done tracking. This is useful for multiple unconnected Cells which use highlighting to inform the user that they are being tracked (like push-buttons and switches).
NX_RADIOMODE is used when you want no more than one Cell to be selected at a time. It can be used to create a set of buttons of which one and only one is selected (there is the option of allowing no button to be selected). Any time a Cell is selected, the previously selected Cell is unselected. The canonical example of this mode is a set of radio buttons.
NX_LISTMODE is the opposite of NX_TRACKMODE. Cells are highlighted, but don't track the mouse. This mode can be used to select a range of text values, for example. Matrix supports the standard multiple-selection paradigms of dragging to select, using the shift key to make disjoint selections, and using the alternate key to extend selections.
The best way to learn about selection modes is to play with a Matrix in Interface Builder, testing the Matrix interface with various options and Cell types. You can also create minimal connections to Buttons that play sounds, setting the action to be performClick:, which will cause the sounds to be played when you use the Matrix in Interface Builder's test mode. |
unsigned int highlightMode:1;
initFrame: