CodeGuru Staff

I have tried the DrawState function before writing one of my own. However, what I have got disappointed me because I found that often, some colors are badly converted from the original image and disapear into the result. I have attached to this message a sample bitmap which shows very well the difference between DrawState() […]

When you select an icon in Windows 95 or NT 4.0, the icon appearance is changed to indicate that it is selected. What Windows does is that it turns every other pixel in the image to the highlight color which is usually blue. The ShadeRect() function shown below executes the same effect on any rectangular […]

Drawing a bitmap transparently means that only those pixels that are not the designated transparent color are drawn onto the target device context. The pixels on the target device context that correspond to a transparent pixel in the source is left unchanged. Any color may be designated as being transparent. If you are drawing the […]

Suppose you have some text and instead of using a single color to draw the text you want the text to be drawn using a bitmap pattern. This is best explained with pictures. The left most image is some text and a simple shape. The image in the middle is the bitmap we want to […]

If you are targeting your application for Windows NT alone, then you have access to API functions to help you rotate the bitmap. You can either use world transformation and BitBlt() or use PlgBlt() for rotating the bitmap. A function using the first combination is shown below. If you are targeting multiple platforms, then your […]

It is possible to invert a bitmap (laterally or vertically) IN-PLACE – ie. without creating any intermediate or temporary bitmaps. You can modify the original bitmap directly. This can be very useful if you are wanting to reflect a LARGE bitmap, and don’t want to allocate the extra storage. The operation requires 50% more StretchBlt […]

We can invert an image either laterally or vertically. The effect of the inversions is shown in the image below. The image on the top left is the normal image, the image on the top right is laterally inverted, the image on the bottom left is vertically inverted and the image on the bottom right […]

Consider that your window has a white background and you need to draw an image on it. You could either simply draw the image or for effect you could let the image fade in from the white background. On the other hand if you already have an image on the window and you want to […]

A device-dependent bitmap (DDB) is structured in such a way that it matches very closely the form in which the bitmap is finally displayed by the device driver. For this reason the DDB is unlikely to be compatible with other display devices. A device-independent bitmap (DIB) on the other hand has a logical layout and […]

You can render a device-independent bitmap (DIB) onto a device without having to convert it into a device-dependent bitmap (DDB). However, the process is slower when using a DIB and you also don’t have access to few very versatile functions such as BitBlt() which handle only DDBs. The basic steps involved in creating a device-dependent […]

To save the image of a window to a BMP file, you have to draw the image to a compatible memory device context, convert the bitmap associated with the memory DC to a device-independent bitmap and then write the DIB to a file. In previous sections, we have already covered how to get a DIB […]