tformimage help?

BlitzPlus Forums/BlitzPlus Programming/tformimage help?

Binary_Moon

(Posted 2003) [#1]

Could someone explain the tform image command please?

I get what it does but the docs are as good as useless when it comes to explaining how it works.

EOF	(Posted 2003) [#2]

Have a look at these screenies.
They each show what the individual TFormImage parameters do:

Command format
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TFormImage image,a#,b#,c#,d#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

a# stretches the image horizontally

b# shears the image vertically

c# shears the image horizontally

d# stretches the image vertically

The amount of shear/stretching depends on what values are supplied.
As you can see from the screenshots, both positive and negative values can be used.
However, setting a# or d# to zero causes an error.

Some examples:

TFormIMage img,2,0,0,1 ; double image width
TFormIMage img,1,0,0,-1 ; flip image vertically

Binary_Moon

(Posted 2003) [#3]

Thanks

That helped. I had tried going through and playing with values but it wasn't working. I'm guessing thats because of the not having 0 on 'a' or 'd'.

Myke-P

(Posted 2003) [#4]

Now *that* is a damned fine explanitory set of pics Syntax. :)

Ross C

(Posted 2003) [#5]

is tform image quicker than using scaleimage?

Binary_Moon

(Posted 2003) [#6]

AFAIK the speed is about the same, although I haven't tested it. The main advantage is the fact you can shear images.

MrCredo

(Posted 2003) [#7]

oh je oh je...

here is my code:

Dim matrix#(3)
bild=CreateImage(50,50)
SetBuffer ImageBuffer(bild)
ClsColor 255,0,0
Cls
Color 255,255,255
Line 0,0,49,49
SetBuffer FrontBuffer()

DrawBlock bild,0,0
bild2=CopyImage(bild)

matrixreset()
matrixscale(2,1)
matrixrotate(-30)
TFormImage bild,matrix(0),matrix(1),matrix(2),matrix(3)
DrawBlock bild,0,130

matrixreset()
matrixrotate(-30)
matrixscale(2,1)
TFormImage bild2,matrix(0),matrix(1),matrix(2),matrix(3)
DrawBlock bild2,0,220

Text 150,0,"original"
Text 150,130,"scale+rotate":Text 150,145,"in 1 operation"
Text 150,220,"rotate+scale":Text 150,235,"in 1 operation"

WaitKey()
End

Function matrixreset()
matrix#(0)=1
matrix#(1)=0
matrix#(2)=0
matrix#(3)=1
End Function

Function matrixrotate(winkel#)
m0#=Cos(winkel#)
m1#=Sin(winkel#)
m2#=-Sin(winkel#)
m3#=Cos(winkel#)
matrixmultiply(m0#,m1#,m2#,m3#)
End Function

Function matrixscale(sx#,sy#)
m0#=sx#
m1#=0
m2#=0
m3#=sy#
matrixmultiply(m0#,m1#,m2#,m3#)
End Function

Function matrixmultiply(m0#,m1#,m2#,m3#)
x0#=matrix#(0)*m0#+matrix#(1)*m2#
x1#=matrix#(0)*m1#+matrix#(1)*m3#
x2#=matrix#(2)*m0#+matrix#(3)*m2#
x3#=matrix#(2)*m1#+matrix#(3)*m3#
matrix#(0)=x0#
matrix#(1)=x1#
matrix#(2)=x2#
matrix#(3)=x3#
End Function

Ross C

(Posted 2003) [#8]

ok, thanks alot :)

DJWoodgate

(Posted 2003) [#9]

Nice. Methinks Syntax Error's and Mr Credo's contributions should be in the docs.

Mark Tiffany

(Posted 2003) [#10]

Absolutely, I intend to do that soonish...but currently we don't have a means of including images in the docs. So I need to come up with a single code example that explains the whole lot...

Mark Tiffany

(Posted 2003) [#11]

Online documentation has been updated, with a heavily modified version of the example above.