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QGrid is a unique 4D plug-in that lets you have on your 4D forms the familiar picture grid view (also known as "contact sheet"). This form of presentation, backed by QGrid's powerful customization features, freedom in selecting data sources, and drag and drop, is instrumental to the human interface needs of modern image databases.

The grid area is filled with cells, each containing a picture and a textual caption. Cells flow to fill the grid area, and automatically reflow when the area is resized. Each cell can contain two objects: a picture and a caption, the position and size of which can be controlled precisely by pixel coordinates. Caption text can be formatted by font, size, face, justification and color.

Any 4D picture can be used as a background for all cells; the picture and caption objects will be shown on top of this background. This feature enhances the appearance of the grid, eg by letting you imitate the look of popular media cataloguers.

Data sources can generally be anything that returns picture or text. The picture and caption sources are described by means of 4D expressions (methods or simple expressions) that return the data type that is appropriate in each case. Using expressions provides both power and freedom to the developer.

Because contact sheets are a primary interface element, end-users are provided with handy ways for selecting cells. QGrid allows for single or multiple selection, supports keyboard modifiers, and returns the user selection in a 4D array for the developer's action. User selection is indicated by means of a rectangular frame around the selected cell (frame color and thickness are controlled programmatically).

Drag and drop is also supported. One or many selected cells can be dragged and dropped at another location of the same QGrid area, or onto another QGrid area, in the same or another 4D process. The visual feedback of the drag and drop action is customizable by the developer.