Android Digital Image formats:lossless versus lossy
- gif is not recommended on Androd OS, cause is lossless , it doesn ' t away image data to achieve better compression results.
- JEPG is lossy digial image file format. It'll thorws away I Mage data in order ot achieve smaller file sizes. and is unrecoverable after compression. So, make sure to save an orginal uncopressed image File
- andoid also support WEBP image format.
The foundation of digital iamges:pixels and aspect ratio
- To found the number of pixels and image, simplely multiply the width pixels by height pixels.
- Aspec ratio would define how square or rectangular a image or display screen is.
The color of digital Imagel:color theory and color depth
- Color values for iamge pixels is defined by the amount of there different colors:red, green, and blue.
- The number of bits used to repersent coloer in a igital image was referred to as the color depth f the image.
- The lowest color depth exists in a 8-bit indexed color image, which has a CLOLR value. It used for GIF and PNG8 formats. The medium color depth image features a 16-bit color depth which contains 65536 colors. But it's not a supported by Android OS. A high color depth iamge features a 24-bit color. Include JPEG, Png,tiff and WebP.
- Using 24-bit color depth'll give you to the Hightset quality level. Since it ' s lossless, it has the highest quality compression.
Representing colors in Androd:hexadecimal Notation
- It's also important to note this in andoid. Color was not the only used in 2D digital iamgery. Also called Itmap imagery.
- #FFFFFF represents a color of whit. As each slot in this 24-bit hexadecimal representation represents on base value. To get the $2 slots for each RGB color would take.
- It's important to note this there is also a 32-bits image color depth whose data values were represented using an ARGB. Whre the A stand for Alpha. Which is a short for alpha channel.
The Alpha stand for transparency.
Image compositing:alpha channels and Blending Modes
- Blending modes is implemented in Android using the Porterduff class.
Some of Android ' s porterduff blending modes include ADD, screen, OVERLAY, darken, XOR, lighten, and MULTIPLY.
Digital Image masking:a Popular use for Alpha Channels
- One of the primary applications for Alpha channels are to mask out areas of an image for compositing.
- Masking is the process of cutting subject matter out of a image and placing it onto its own layer using an alpha channel.
- You can ' t really does effective image compositing without doing masking first, so it's an important area for graphics design ERs to master.
- Masking can be do by using selection tools and sharpening and blur algorithms
Ch1:android Digital imaging:formats Concepts and optimization