Comments on Real Software: Drawing multiple color gradients

I've decided to take part of the challenge. He...

2009-08-28T03:26:23.651-05:00

I've decided to take part of the challenge. Here's the code to create radial gradients:

Function CreateRadialGradient(Width As Integer, Height As Integer, Points() As Pair) As Picture
// Change this constant to modify the quality. The higher the number, the more
// passes will be made to refine the gradient, at the cost of rendering speed.
const quality = 50

dim p as new picture(width,height,32)
dim i,x,y,v,w,h,s,e as integer
dim pointOne,pointTwo as pair
dim colorOne,colorTwo,blendedColor as color
dim pct,amt as double
dim curLeft,curTop,curWidth,curHeight,destLeft,destTop,destWidth,destHeight as integer

p.graphics.forecolor = points(0).right.colorvalue
p.graphics.fillrect(0,0,p.width,p.height)

for i = 0 to ubound(points) - 1
pointone = points(i)
pointtwo = points(i + 1)
colorone = pointone.right
colortwo = pointtwo.right

destwidth = ((1 - pointtwo.left.doublevalue) * width)
destheight = ((1 - pointtwo.left.doublevalue) * height)
destleft = curleft + (destwidth / 2)
desttop = curtop + (destheight / 2)
curwidth = (1 - pointone.left.doublevalue) * width
curheight = (1 - pointone.left.doublevalue) * height

s = pointone.left.doublevalue * quality
e = pointtwo.left.doublevalue * quality
for v = s to e
amt = v / quality
x = amt * (width / 2)
y = amt * (height / 2)
w = width * (1 - (v / quality))
h = height * (1 - (v / quality))
pct = (v - s) / (e - s)
blendedcolor = rgb((colorone.red * (1 - pct)) + (colortwo.red * pct),(colorone.green * (1 - pct)) + (colortwo.green * pct),(colorone.blue * (1 - pct)) + (colortwo.blue * pct))
p.graphics.forecolor = blendedcolor
p.graphics.filloval(x,y,w,h)
next

curleft = curleft + destleft
curtop = curtop + desttop
next

return p
End Function

Not sure how well that code will appear in the comments though.

Ahhhh but your missing the point of a screenshot r...

2009-08-27T11:25:56.357-05:00

Ahhhh but your missing the point of a screenshot request -- it's for users who DO NOT HAVE REALbasic installed.
For example, I'm posting this from a BlackBerry.

@Anonymous: It took me four minutes to paste Thom&...

2009-08-26T02:47:44.760-05:00

@Anonymous: It took me four minutes to paste Thom's code into a project and test it.
I've put a very amateurish screenshot at
http://rbjottings.co.uk/picstuff/gradient.png

How about providing a couple of screenshots of the...

2009-08-25T23:27:28.493-05:00

How about providing a couple of screenshots of the effect. Nothing large; doesn't even need to be the entire window -- just a snapshot of what the code does.

Angled gradients are probably the more difficult. ...

2009-08-23T13:29:33.852-05:00

Angled gradients are probably the more difficult. You basically need to recall some high school math and draw lines. Radials are simple, draw circles.

That sounds really good but what if you needed to ...

2009-08-22T18:52:37.255-05:00

That sounds really good but what if you needed to draw the gradient at an angle? Or even harder - radial gradients. How might one tackle that?

Thanks much.