Some Issues When Using csXImage with VB.NET
Below are listed some programming techniques that are necessary when using an ActiveX control in VB.NET. They are relevant to the demo that is supplied with csXImage and further description can be found in the readme text file that is supplied with the installer.
- VB.NET cannot directly recognise indexed properties of ActiveX controls, such as the PixelColor property of csXImage. To use these properties, the property name must be prefixed by get_ (to read the property) or by set_ (to write the property). For example, get_PixelColor is used in Sub AxImageBox1_OnMouseMove to read the colour of the pixel under the cursor.
- The data type OLE_COLOR used by, for example, the PixelColor property, is equivalent to the data type System.Drawing.Color in VB.NET.
- In VB.NET, the OnMouseMove event is only triggered if the ImageBox control has the Focus. One effect of this is to prevent the crosshair cursor used by the MouseSelectRectangle and MouseSelectEllipse functions from automatically displaying when the mouse is moved over the control. This issue is solved by adding the line AxImageBox1.Focus( ) as required.
Some downloadable VB.NET examples:
- Introduction to the demo supplied with the trial.
- Zoom - An example of zooming an image.
- File Info - An example of editing IPTC text and EXIF data.
- Rubber Band - Drawing a line with "Rubber Banding".
- Selecting an area - Drawing a selection area with "Rubber Banding".
- Unicode - An example of adding text to an image in Unicode characters.
- TWAIN - An example of capturing an image from a TWAIN compliant scanner or camera.
- ADF - An example of scanning multiple images from a scanner with an Auto Document Feed.
- Multi-page TIFF - View edit or scan multi-page TIFF images.