Assuming that the coordinates of the upper left corner of the original image area are (x0, y0), the coordinates of the lower right corner are (x 1, y 1), and the images are translated by dx and dy along the x and y axes respectively, the coordinates of the upper left corner of the new image are (x0+dx, y0+dy) and the coordinates of the lower right corner are (x 1+dx.
There are four steps to move the image on the screen: (1) Save the original image to the buffer.
(2) Erase the original image.
⑶ Calculate the new coordinates after translation.
(4) Re-display the original image at the new coordinate position.
2. Image inversion Image inversion refers to the inversion of the defined image area on the screen.
By analyzing the process of image inversion, we can find that the image information of each line is unchanged, but the order of lines is changed. The first line is exchanged with the last n line, and the second line is exchanged with n- 1 line, and so on, so as to realize image inversion.
Only by exchanging lines, the contents of the buffer can be easily modified to realize the inversion of the image.
3. Mirror image transformation refers to the upside-down display of images in designated areas on the screen.
Through the analysis of the process of mirror image transformation, it can be found that the image information processing method of each line is the same, and the line order is unchanged, but the pixel information of each line is reversed from left to right, thus realizing mirror image transformation.
Therefore, mirroring is realized by point transformation line by line.
4. Image rotation Image rotation refers to rotating a defined image around a certain point counterclockwise or clockwise for a certain angle. Nanjing computer training/thinking usually refers to rotating counterclockwise around the center of the image.