For this assignment you will be building a Bitmap reader and transformer.
It will read a Bitmap in from disk, run one or more color transforms on the bitmap
and then write it out to a new file.
This project will require the use of node Buffer in order to manipulate binary data.
The process will look something like this:
- Open file using fs and read it into a buffer
- Read the "header" information to get the needed info (you might encapsulate this into an object)
- Run a transform on the buffer based on the header information and the transform you are applying
- Write the buffer to a new file.
The wikipedia article found here Bitmap Specification describes the byte specification of a "windows bitmap file.":
- We'll be working the simplest version, meaning no compression
- The sample files fit "perfectly" in terms of byte size per row
- Your project should include at least one transform.
This can be a difficult assignment so make sure to raise questions early.
Ideas for easy transformations:
- Invert the colors (essentially subtract every color value from the max color value which is 255),
- Grayscale the colors, multiply each color value by a constant, just make sure your values don't go over 255.
- (red|green|blue)scale the colors, same as above but only multiply one of the colors.
Tests:
- You may want to use "pinning" or "snapshot" tests for testing overall transformed bitmap
- Be thoughtful about what to test (and what not to test!)
API:
Think about your library being used by another developer. Distinguish between the interface and your implementation.
- Tests: 3pts
- npm scripts/package.json 2pts
- Read Bitmap Meta Data 5pts
- Successfully Apply Transform 5pts
- Project Design 5pts
- improve your "API" for interfacing with the transformer (it probably could be better)
- handle palette and non-palette bitmaps
- can handle various sized bitmaps (handle padded rows for non-palette bitmaps)
- create a command line interface