العفو

Introduction

The PictureBox control is used to display graphics, to act as a container for other controls, and to display output from graphics methods or text using the Print method.

The Image control is similar to the PictureBox control in that each can be used to display graphics in the Visual Basic application. Both supports the same graphic formats - JPEG, GIF, WMF, EMF, BMP and ICO. However, the PictureBox control contains functionality which the Image control does not. For example, the ability to act as a container for other controls and support for graphics methods.

The Ilixis Developer's Corner is providing a service to developers by providing the
source code of a sample Visual Basic program using the PictureBox control.


Loading Images

Images can be loaded into the PictureBox control or Image control at design- time by selecting the Picture property from the control's Properties window; or at run-time by using the Picture property and the LoadPicture function. To clear the graphic from the PictureBox control or the Image control, use the LoadPicture function without specifying a file name.

Set Picture1.Picture = LoadPicture ("c:\images\test.bmp", vbLPLarge, vbLPColor)


Resizing Images and Controls

The Stretch property determines whether the image is stretched to fit the Image control. If set to TRUE, the image will stretch to fit the control. Otherwise, the control will resize to fit the image. Stretching an image can produce a loss in image quality. However, Metafiles, which are "draw-type" graphics, are better suited for stretching.

By default, images are loaded into a PictureBox control at their original size. If the image is larger than the control, the image will be clipped — the PictureBox control does not provide scroll bars. To make a PictureBox control automatically resize to display an entire image, set its AutoSize property to True. The control will then size to the image by growing or shrinking.

Unlike the Image control, the PictureBox control cannot stretch the image to fit the size of the control.


Graphics Methods (PictureBox Control only)

The PictureBox control can be used to receive the output of graphics methods such as Circle, Line, and Point. For example, you can use the Circle method to draw a circle in a picture box by setting the control's AutoRedraw property to True.

Picture1.AutoRedraw = True
Picture1.Circle (1200, 1000), 750

Setting AutoRedraw to True allows the output from these methods to be drawn to the control and automatically redrawn when the picture box control is resized or redisplayed after being hidden by another object.


Print Method (PictureBox Control only)

The PictureBox control can be used to output text by using the Print method and setting the AutoRedraw property to True. When using the Print method, the font style and size can be modified; and the CurrentX, CurrentY, Height, and Width properties can be used to align text within the PictureBox control.

Picture1.Print "A text string"


Differences between PictureBox and Image controls

The Image control uses fewer system resources and repaints faster than a PictureBox control, but it supports only a subset of the PictureBox control's properties, events, and methods. Both controls support the same picture formats. However, images can be stretched in an Image control to fit the control's size. Stretching cannot be done with the PictureBox control.