The number of bits (not bytes) used per pixel is often abbreviated with the acronym bpp it stands for bits per pixel. If you use three bytes to encode the red, green and blue color of a pixel respectively, you can define up to 16.8 millions different colors. With 1 byte (8 bits) you can encode or represent 256 different values per color. In the old times, when computer memory and disk space were limited, pixels values were often stored using the least possible number of bytes. If you work with an additive color system (which computer screens are using) these colors are red, blue and green (in a subtractive color system these primary colors are cyan, magenta and yellow). A pixel in the digital world is generally defined by three digital values, one for each elementary or primary color. The width (horizontal dimension) and the height (vertical dimension) define the overall resolution of the image. The image resolution defines the dimension of this 2D array. As a quick definition let's just say that an image in the digital world, is stored or represented as a 2D array of pixels. We are familiar with the concept of digital images. In the next lesson, we will extend our basic C++ class to support basic image manipulations.
SIMPLEIMAGE HAS NO ATTRIBUTE READ CODE
Without any further due, let's start to quickly revisit what we know about images and implement some simple code to read and write them as well as store them in memory. You can easily extend this class as an exercise, for example you can use template to define the image data type and the number of channels on the fly. Our basic image class will only support floating point images (a must these days) composed of three channels only. Obviously many designs are possible but we will just stick with a very simple one to start with.
In this lesson, we will also write a very basic Image class which will be extended over time. It seems quite natural as a prerequisite to any of the lessons devoted to image processing that we learn about reading and writing images. Want to report bugs, errors or send feedback? Write at We do this for free, please be kind. Source Code Keywords: image file format, PPM, header, bits per pixel, color depth, high dynamic range image, return value optimization, RVO, copy elision.
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