Apple Newton Utilities Guide de l'utilisateur télécharger pdf (Page 539)

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CHAPTER 13

Drawing and Graphics

Using the Drawing Interface 13-13

If the style frame includes a clipping slot, the drawing of all shapes affected by

this style frame is clipped according to the value of the

clipping slot. If the

value of the

clipping slot is nil or if the clipping slot is not supplied, the

clipping behavior of the destination view is used.

If the

clipping slot contains a region shape, that region is used as the clipping

boundary for drawing operations affected by this style frame. If the

clipping slot

contains an array of shapes or regions, the system passes the contents of the

clipping slot to the MakeRegion function to automatically create a new

clipping region from the contents of this slot.

Note

Although putting an array of shapes in the clipping slot may

seem convenient, it signiﬁcantly increases the time required to

process the style frame. For best performance from the view

system, do not use this shortcut in style frames that are used

repeatedly.

◆

Tran sforming a Shape 13

The transform slot changes the size or location of a shape without altering the

shape itself. It accepts an array specifying an

x, y coordinate pair or a pair of

rectangles. The

x, y coordinate arguments relocate a shape by specifying an offset

from the origin of the destination view’s coordinate plane. The rectangle arguments

specify a mapping of the source and destination views that alters both the size and

location (offset) of the source view when it is drawn in the destination view.

The rectangle arguments work the same way as the parameters to the

ScaleShape function (although transforms won’t accept nil for the boundaries

of the source rectangle): the size of the shape is changed proportionately according

to the dimensions of the destination rectangle, and the coordinates of the

destination rectangle can also be used to draw the shape in a new location.

The following code fragments demonstrate the use of offset coordinates and

mapping rectangles as the value of the

transform slot:

transform: [30,50],// offset shapes by 30 h and 50 v

transform:

[SetBounds(0,0,100,100),SetBounds(25,25,75,75)],

// half width and height, centered in relation to

// the original object(not the view) assuming that

// the first rect actually specified correct bounds

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Apple Newton Utilities Guide de l'utilisateur Page 539

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