1. Image Editing II

2. Simple Blending =.7 x+.5 x Each pixel in a layer is multiplied by the same opacity value

3. Simple Blending =+ xx Opacity values can be visualized as gray levels 0.70.5

4. Each pixel in a layer can have a different opacity value The opacity values for a layer’s pixels can be visualized as a grayscale image This grayscale image is called a “mask” Complex Blending

5. =+ xx Layer Masks

6. Selection Mask One bit for each pixel 1 = selected 0 = not selected

7. Selection Mask ImageSelectMask Selecting all yellow and some red pixels

8. Copy ImageSelectMask PasteImagePasteMask

9. Copy Algorithm for (every pixel [x,y] in the image) { if (selectMask[x,y] == 1) { pasteImage[x,y] = image[x,y]; pasteMask[x,y] = 1; } else { pasteMask[x,y] = 0; }

10. Layer Composition Algorithm Layer = mask+image Image for (every pixel [x,y] in the layer) { if (mask[x,y] == 1) { new[x,y] = layer[x,y]; } else { new[x,y] = image[x,y]; } New

11. Moving a Layer

12. Layer = mask+image Image New Move layer pixels without touching image pixels

13. Cut What happens to the deleted pixels? Replace with background color

14. Picture Editing

15. Object representations of pictures Types of objects –Lines –Rectangles –Ovals –Text –Curves –Pictures Text

16. Picture = array of drawing objects 0) Rect(10,10,50,40,tan,yellow) 1) Oval(0,30,40,20,blue,purple) 2) Line(20,0,20,80,gray)

17. Adding an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval(0,30,40,20,blue,purple) 2) Line(20,0,20,80,gray) 3) Text(25,25,”Hello”, black,”Times” ) Hello

18. Selecting an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval(0,30,40,20,blue,purple) 2) Line(20,0,20,80,gray) 3) Text(25,25,”Hello”, black,”Times” ) Hello CurObj = 2

19. Deleting an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval(0,30,40,20,blue,purple) 2) Line(20,0,20,80,gray) 3) Text(25,25,”Hello”, black,”Times” ) Hello CurObj = 2

20. Deleting an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval(0,30,40,20,blue,purple) 2) Text(25,25,”Hello”, black,”Times” ) Hello CurObj = Why no missing pixels?

21. Deleting an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval(0,30,40,20,blue,purple) 2) Text(25,25,”Hello”, black,”Times” ) Hello CurObj = Does object delete work like images or like text?

22. Moving an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval(0,30,40,20,blue,purple) 2) Text(25,25,”Hello”, black,”Times” ) Hello

23. Moving an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval( 30,30,40,20,blue,purple) 2) Text(25,25,”Hello”, black,”Times” ) Hello

24. Changing an object 0) Rect(10,10,50,40,tan,yellow) 1) Oval(30,30,40,20,blue,purple) 2) Text(25,25,”Hello”, red,”Arial” ) Hello

25. Move an object back

26. 0) Oval(30,30,40,20,blue,purple) 1) Rect(10,10,50,40,tan,yellow) 2) Text(25,25,”Hello”, red,”Arial” ) Hello

27. Changing an image Sequoa -> Sequoia Select the “a” with magic wand

28. Changing an image Sequoa -> Sequoia Drag the “a” to the right Leaves ugly blank pixels

29. Change using objects Sequoa Select text insertion point Image object Text object

30. Change using objects Sequoia Image object Text object

31. Compare Why are images better than objects? –More realistic pictures –Easy to generate with cameras and scanners Why are objects better than images? –Less space –Easier to make changes