CMPT 166 Lecture Notes - Lecture 34: Ellipse, Complete Control, Moon

• School: Simon Fraser University
• Department: Computing Science
• Course: CMPT 166
• Professor: Steven Pearce

Document Summary

These notes introduce two very useful geometric transformations: rotation and translation. Recall that processing treats the screen as a rectangular array of pixels. By default, processing labels each pixel in (column, row) form, starting at 0 in both the rows and columns. Thus, on the screen, the pixel in the upper-left corner is (0, 0), because it is in row 0 and column 0. In other words, we can say that the default coordinate system for processing puts the origin point (0: in the upper-left corner of the screen, and the x-axis and y-axis are parallel to the sides of the screen. As we will see, processing lets you move the origin, and also rotate the entire coordinate system around the origin. By combining sequences of rotations and translations, you have complete control over the location and orientation of any object. Translation is a geometric term that means move .