Grid  - AS3 Flex

Constructor.

Calculates the preferred, minimum, and maximum sizes of the Grid.

You should not call this method directly; it is an advanced method for use in subclassing. The Flex LayoutManger calls the measure() method at the appropriate time. At application startup, the Flex LayoutManager attempts to measure all components from the children to the parents before setting them to their final sizes.

To understand how the Grid container calculates its measurements, assume that every GridItem container has its rowSpan property and colSpan property set to 1. The measured width of the first column of the Grid container is equal to the maximum among of the measured widths of all GridItem containers in the first column. Similarly, the measured width of the second column is the maximum of all measured widths among the GridItem containers in the second column, and so on. The measuredWidth of the entire Grid container is the sum of all columns' measured widths, plus the thickness of the border, plus the left and right padding, plus room for the horizontal gap between adjacent grid cells.

The measuredHeight, minWidth, minHeight, maxWidth, and maxHeight properties' values are all calculated in a similar manner, by adding together the values of the GridItem containers' measuredHeight properties, minWidth properties, and so on.

If a GridItem container's colSpan property is 3, that GridItem container's measuredWidth is divided among 3 columns. If the measuredWidth is divided equally, each of the three columns calculates its measured width as if the GridItem container were only in that column and the GridItem container's measuredWidth were one-third of its actual value.

However, the GridItem container's measuredWidth property is not always divided equally among all the columns it spans. If some of the columns have a property with a percentage value of width, the GridItem container's measuredWidth property is divided accordingly, attempting to give each column the requested percentage of the Grid container.

All of the values described previously are the measured widths and heights of Grid. The user can override the measured values by explicitly supplying a value for the following properties:

• minHeight
• minWidth
• maxHeight
• maxWidth
• height
• width

If you override this method, your implementation must call the super.measure() method or set the measuredHeight and measuredWidth properties. You may also optionally set the following properties:

• measuredMinWidth
• measuredMinHeight

These properties correspond to the layout properties listed previously and, therefore, are not documented separately.

Sets the size and position of each child of the Grid.

You should not call this method directly; it is an advanced method for use in subclassing. The Flex LayoutManager calls the updateDisplayList method at the appropriate time. At application startup, the Flex LayoutManager calls the updateDisplayList() method on every component, starting with the root and working downward.

The Grid container follows the same layout rules as the VBox container. The positions and sizes of the GridRow containers are calculated the same way that a VBox container determines the positions and sizes of its children. Similarly, a GridRow container positions its GridItem containers using a similar layout algorithm of an HBox container.

The only difference is that the GridRow containers all coordinate with one another, so they all choose the same positions and sizes for their children (so that the columns of the Grid container align).

If you override this method, your implementation should call the super.updateDisplayList() method and call the move() and the setActualSize() methods on each of the children. For the purposes of performing layout, you should get the size of this container from the unscaledWidth and unscaledHeight properties, not the width and height properties. The width and height properties do not take into account the values of the scaleX and scaleY properties for this container.

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