PureImageConverter

usage

Just call ./vimgconvert <path_to_file.png>

input

Input format is 3 channel (RGB) or 4 channel (RGBA, A for alpha).

Alpha (transparency) works like this: any alpha value other than fully opaque (255) will cause given pixel not to be drawn. Alpha channel is essentially a mask with threshold of 254.

Exapmle images:

• transparent backgroud (32×32, monochrome objects, backgroud alpha=0):

• 16-step grayscale gradient (32×32, 16 gray levels ranging from 0 to 255, no alpha channel)

alpha details

Alpha is internally stored as a colour. It gets compared in Renderer.cpp against regular colours. If there is a match with current stroke, then this stroke is skipped. Therefore alpha isn't really a channel, but a colour i.e. there is no property of alpha. A pixel can be either black, gray, white or translucent. No gradation here.

By default it is a colour number 16 as this doesn't make sense as a colour. There are only 16 colours, namely 0-15. You can override this defualt behaviour by specifying which colour will be treated as alpha for displaying purposes. To do so, pass a number (0-15 are valid colours) as the second argument e.g. ./vimgconvert image.png 3

output

VPI - vector format MPI - bitmap (?) format.

VPI format

vector means not vector as in SVG, but strokes. image is composed from strokes of colour from top left corner, horizontally, to bottom right.

header

there is a header:

uint16_t width
uint16_t height
uint8_t  alpha colour

and then raw data.

output

The program outputs given vectors as debug info:

<no. of unique vectors per line> [<vecOffset> <vecLength> <vecColor>]

e.g.

2 [0,10,8][0,22,15]