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by a combination of ‘full characters’ which contain 5 bars each, followed by a terminal
character containing less than 5 bars. For example, a bar graph of length 27 will be 5 full
characters (5*5=25), followed by a character containing the last 2 bars:
Bar of 27 units =
5 Filled Characters +
1 Partially Filled
Character
We can calculate the number of full characters by integer division: length/5. And the
number of bars in the final, partially filled character is just the remainder: length % 5. A
function for writing the horizontal bar sends the required number of solidly-filled characters,
then a single, partially-filled character. Assume that the symbols have previously been
loaded into the character-generator RAM at positions 0 through 4.
def DrawHBar(row,length):
fullChars = length / 5
bars = length % 5
GotoXY(row,0) #start at beginning of row
for count in range(fullChars): #full characters sent first
SendByte(4,True)
if bars>0: #final, partially filled character
SendByte(bars-1,True)
The call to SendByte(4,True) sends the fourth symbol in CG-RAM, which is the 5-bar (filled)
character.
4) ANIMATED HORIZONTAL BAR GRAPHS
The graphs are nice, and fun to watch a few times. But looking at fat lines gets dull after a
while. Let’s spice them up a bit, and add some animation like we did in part 3 with the
‘battery charging’ symbol.
To animate the graph, we need two key functions: one to increment the graph length, and
one to decrement it. Then animation becomes the simple task of keeping track of how
many increments/decrements to do. Using a top-down approach, lets write this function
first, and worry about the increment/decrement later.
def AnimatedHBar(row,startCol,newLength,oldLength=0):
diff = newLength - oldLength
for count in range(abs(diff)):
if diff>0:
IncrementHBar(row,startCol,oldLength)
oldLength +=1
else:
DecrementHBar(row,startCol,oldLength)
oldLength -=1