Bitmapped Graphics

Understanding Bitmapped Graphics

  • A Bitmapped Graphic is a type of image which is made up of pixels - the smallest possible unit of an image.
  • Each pixel has its own value or colour depth which represents its colour.
  • The size of a bitmapped graphic can be determined through its width and height in pixels, also known as its resolution.

Advantages and Disadvantages of Bitmapped Graphics

  • One key advantage of bitmapped graphics is their ability to represent highly complex and detailed images. They are ideal for complex images with a wide range of colours such as photographs.
  • A downside of bitmapped graphics is that as you zoom in or enlarge the image, the quality deteriorates leading to “pixelation”.
  • Another disadvantage is their file size. As the resolution of the image increases, so does its file size. This is because each pixel requires storage.

The Role of Colour Depth in Bitmapped Graphics

  • Colour depth refers to the amount of data that can be stored for each pixel in the graphic.
  • The larger the colour depth, the more colours a pixel can potentially display, which can lead to a more vibrant and accurate representation of colour.
  • However, a higher colour depth also needs more storage, meaning larger file sizes.

Understanding Image Metadata

  • An image file often includes more than just the pixel data. This can include information like the image’s dimensions, the camera used to capture it, and even geographical coordinates where the picture was taken.
  • This additional data is known as metadata. While it can be really useful, metadata also increases the size of the image file.

Bitmapped File Formats

  • Common bitmapped file formats include JPEG, GIF, BMP, and PNG, each with their own pros and cons.
  • JPEG is a lossy compression format widely used for photographs. It can achieve high compression ratios but at the cost of some loss of quality.
  • GIF is suited for simple images with a limited colour palette. It also supports animation.
  • BMP is a very simple format that doesn’t use compression. This results in high-quality images but large file sizes.
  • PNG is a lossless compression format that supports a large colour depth. It’s a good choice for high-quality images, but the file sizes can be quite large.

Compression and Bitmapped Graphics

  • Image files can be made smaller using compression. Techniques used can either be lossy, where some detail is lost, or lossless, where the original image can be exactly recreated.
  • Compression is especially important for bitmapped graphics due to their potential large size. Using compression can make these images more practical for use on the web or for storage.