These are also known as pixelmaps and raster images. These are images that are made of pixels (a two-dimensional matrix), so your typical PNGs and JPEGs are bitmaps. These pixels can be rectangular or cicular.
Colours are displayed by varying the intensity of red, green and blue in each pixel.
Some important terms:
The number of bits used to represent the colours of one pixel.
The number of bits used to represent the intensity of red, green and blue (individually) in a pixel.
The product of the dimensions of the image (width * height).
The product of the dimensions of the screen (width * height).
The number of pixels per square inch (PPI, if you're familiar with that terminology).
A greater colour depth, bit depth, or image resolution will result in larger file sizes.
The reason why zooming into a bitmap image appears to reduce its quality is because the pixels of the image is scaled as you zoom. The more you zoom, the larger the pixels become. Larger pixels reduce image quality, and can make an image look blurry.
The procedure to remember is to multiply the image resolution with the colour depth. If the bit depth is provided, then we sum those values to get our colour depth.
File headers are a set of bytes located at the beginning of a bitmap file. These bytes identify the file type and the coding used.
Simply put, more bandwidth is required to access these images, since it would have a larger file size. Uploading/downloading images takes longer and requires more bandwidth. Storing them requires more disk space. So on and so forth.
Vector graphics make use of coordinates and geometry (coordinate geometry) to define shapes.
Vector files include a "drawing list" in their file header. It contains:
Vector images are produced on-demand, through the information present in the drawing list. Calculations are made to produce each object, the attributes are applied, and they are positioned appropriately at a suitable scale. If the scale changes, then these calculations are performed again.
| Vector graphics | Bitmap images |
|---|---|
| composed of geometric shapes | composed of pixels |
| changes are made to the shapes when edited, which may affect the properties of others | changes can be made to individual pixels only |
| smaller in size, since the image is produced on the basis of math | larger size, since pixels require an amount of bits to store |
| not suitable for realistic imagery | suitable for realisitc imagery |
| file formats include .svg, .cgm, .odg | file formats include .jpg, .png, .bmp |
The choice of using either type of image depends on the kind of work you want done.
For images where scalability is important, vectors may prove superior. If realism is a priority, then bitmaps have an advantage. If there are restrictions on file size, vectors. You get the point.
This article was written on 23/09/2023. If you have any thoughts, feel free to send me an email with them. Have a nice day!