1. Picture Functions ppp =makePicture(pickAFile())
ppp.getWidth(), ppp.getHeight()
xxx=ppp.getPixel( , )
xxx.getColor(), .getRed(), .getGreen(), .getBlue()
xxx.setColor(), .setRed(), .setGreen(), .setBlue()
makeColor(), pickAColor()
setMediaPath() – fix a path to media files
getMediaPath(filename)
file = makeEmptyPicture(100,100) – creates a blank picture of size 100x100
writePictureTo(file, “100x100.jpg”) – save file with name “100x100.jpg”

2. Copy to a blank canvas
Download and
targetX = sourceX
targetY = sourceY
sourceX
sourceY
flower1
canvas

3. Picture Copy Function picCopy() with a picture into a larger canvas
Convert the copying operation below to picCopy() and main()
pict = makePicture(pickAFile()) # flower1.jpg
canvas = makeEmptyPicture(1000,800)
hgt = pict.getHeight()
wid = pict.getWidth()
repaint(canvas)
def picCopy(fPic, tPic, fx, fy):
return canvas
# main()
pict = makePicture(pickAFile()) # flower1.jpg
canvas = makeEmptyPicture(1000,800)
picCopy(pict, canvas, 0, 0)
repaint(canvas)

4. Copy flower2 targetX = sourceX + getWidth(flower1) targetY = sourceY

5. Making a collage Given a blank canvas
Copy flower1 at upper left corner of canvas
Copy flower2 next
Copy negated flower1
Copy flower2 with blue removed
Copy flower1, negated and red reduced

6. Put them together #First picture, at left edge targetX=1
for sourceX in range(1, getWidth(flower1)):
targetY=1
for sourceY in range(1,getHeight(flower1)):
px=getPixel(flower1,sourceX,sourceY)
canvas_x=getPixel(canvas,targetX,targetY)
setColor(canvas_x,getColor(px))
targetY=targetY + 1
targetX=targetX + 1
#Second picture, 100 pixels over
targetX= getWidth(flower1) # 100
for sourceX in range(1,getWidth(flower2)):
targetY= 1
for sourceY in range(1,getHeight(flower2)):
px=getPixel(flower2,sourceX,sourceY)
canvas_x=getPixel(canvas,targetX,targetY)
setColor(canvas_x,getColor(px))
targetY=targetY + 1
targetX=targetX + 1

7. Collage: Code def createCollage():
flower1=makePicture(getMediaPath("flower1.jpg"))
print flower1
flower2=makePicture(getMediaPath("flower2.jpg"))
print flower2
canvas=makePicture(getMediaPath("640x480.jpg"))
print canvas
#First picture, at left edge
targetX=1
for sourceX in range(1,getWidth(flower1)):
targetY=1
for sourceY in range(1,getHeight(flower1)):
px=getPixel(flower1,sourceX,sourceY)
cx=getPixel(canvas,targetX,targetY)
setColor(cx,getColor(px))
targetY=targetY + 1
targetX=targetX + 1
#Second picture, 100 pixels over
targetX=100
for sourceX in range(1,getWidth(flower2)):
for sourceY in range(1,getHeight(flower2)):
px=getPixel(flower2,sourceX,sourceY)
#Third picture, flower1 negated
negative(flower1)
targetX=200
for sourceX in range(1,getWidth(flower1)):
targetY=1
for sourceY in range(1,getHeight(flower1)):
px=getPixel(flower1,sourceX,sourceY)
cx=getPixel(canvas,targetX,targetY)
setColor(cx,getColor(px))
targetY=targetY + 1
targetX=targetX + 1
#Fourth picture, flower2 with no blue
clearBlue(flower2)
targetX=300
for sourceX in range(1,getWidth(flower2)):
targetY= 1
for sourceY in range(1,getHeight(flower2)):
px=getPixel(flower2,sourceX,sourceY)
#Fifth picture, flower1, negated with decreased red
…….
show(canvas)
return(canvas)

8. General picCopy()
If we had a general picCopy(pic, targetPic, targetX, targetY)
createCollage()
picCopy(flower1, canvas, 0, 0)
picCopy(flower2, canvas, getWidth(flower1), 0)
picCopy(negate(flower1), canvas, getWidth(flower1) + getWidth(flower2), 0)
picCopy(clearBlue(flower2), canvas, getWidth(flower1)*2 + getWidth(flower2), 0)
picCopy(reduceRed(negate(flower1)), canvas, getWidth(flower1)*2 + getWidth(flower2)*2, 0)

9. Encapsulation
Once picCopy(pic, targetPic, targetX, targetY) is written
View a collage
A collection of high-level picture manipulation
Don’t worry about the details of negate, reduceRed, etc.
In cooking recipe,
Do not worry about how wheat is processed into flour, …
Encapsulation -> Information Hiding