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I modified Gary's Bezier curves program from https://forum.powerbasic.com/forum/u...956#post657956
I gotten it to draw the hockey stick, but the graphics is upside as below shown, how do I make it right side up with the Y-axis pointing upwards?
Listing is as below
I gotten it to draw the hockey stick, but the graphics is upside as below shown, how do I make it right side up with the Y-axis pointing upwards?
Listing is as below
Code:
' Draw Bezier.bas
' https://forum.powerbasic.com/forum/user-to-user-discussions/powerbasic-for-windows/55060-draw-smooth-curve-from-series-of-points-discussion?p=657956#post657956
#COMPILE EXE
#DIM ALL
%Unicode = 1
#INCLUDE "Win32API.inc"
%IDC_Graphic = 500
GLOBAL hDlg AS DWORD
GLOBAL Gp() AS POINT
GLOBAL GpCount AS LONG
FUNCTION PBMAIN() AS LONG
DIALOG NEW PIXELS, 0, "Click on graphics to display another set of curves",_
60,100,500,500, %WS_OVERLAPPEDWINDOW TO hDlg
CONTROL ADD GRAPHIC, hDlg, %IDC_Graphic, "", 0, 0, 500,500, %SS_NOTIFY
GRAPHIC ATTACH hDlg, %IDC_Graphic, REDRAW
DIALOG SHOW MODAL hDlg CALL DlgProc
END FUNCTION
CALLBACK FUNCTION DlgProc() AS LONG
SELECT CASE CB.MSG
CASE %WM_INITDIALOG
RANDOMIZE TIMER
' create the hockey stick image
CrPoints_Hockey
' varying these values of dt and Tension
' can smoothen the curves
' DrawCurves 0.75,0.01 ' 0.5 ' 10,1
DrawCurves 0.5 ,0.25
CASE %WM_COMMAND
SELECT CASE CB.CTL
CASE %IDC_Graphic
' when the graphics is clicked the
' curves is redrawn randomly
' initialize the points randomly
MovePoints(1)
DrawCurves 0.01, 0.5
END SELECT
END SELECT
END FUNCTION
' Initialize the points with random values
SUB MovePoints(Initialize AS LONG)
LOCAL i AS LONG
IF Initialize THEN
'initialize points
GpCount = 20 : REDIM Gp(19)
FOR i = 0 TO 18
Gp(i).x = RND(100,300) : Gp(i).y = RND(100,300)
NEXT i : Gp(19) = Gp(0)
ELSE
'move points
FOR i = 0 TO 18
Gp(i).x += RND(-1,1) : Gp(i).y += RND(-1,1)
NEXT i
Gp(19) = Gp(0)
END IF
END SUB
' create the hockey stick image
' allocate the points in a clockwise manner
' to form the close loop image
SUB CrPoints_Hockey
LOCAL scaleXY AS DOUBLE
' scale to fit the graph
scaleXY = 20
' note that points start from sequence = 0
REDIM Gp(17)
Gp(0).x = 5.25 * scaleXY
Gp(0).y = 20 * scaleXY
Gp(1).x = 5.25 * scaleXY
Gp(1).y = 20 * scaleXY
Gp(2).x = 5.75* scaleXY
Gp(2).y = 20* scaleXY
Gp(3).x = 6 * scaleXY
Gp(3).y = 17 * scaleXY
Gp(4).x = 6.5 * scaleXY
Gp(4).y = 5 * scaleXY
' trough before the uphook
Gp(5).x = 7.15 * scaleXY
Gp(5).y = 4.3 * scaleXY '4.3
Gp(6).x = 8* scaleXY
Gp(6).y = 5 * scaleXY
Gp(7).x = 8.8* scaleXY
Gp(7).y = 6.8* scaleXY
' tip of the uphook
Gp(8).x = 9.5* scaleXY
Gp(8).y = 7.* scaleXY
Gp(9).x = 10 * scaleXY
Gp(9).y = 6.3 * scaleXY
Gp(10).x = 8.8 * scaleXY
Gp(10).y = 3.1 * scaleXY
Gp(11).x = 8.5 * scaleXY
Gp(11).y = 3 * scaleXY
Gp(12).x = 8 * scaleXY
Gp(12).y = 2.8 * scaleXY
Gp(13).x = 6.1 * scaleXY
Gp(13).y = 2.8 * scaleXY
Gp(14).x = 5.5 * scaleXY
Gp(14).y = 3 * scaleXY
Gp(15).x = 5 * scaleXY
Gp(15).y = 4 * scaleXY
Gp(16).x = 5 * scaleXY
Gp(16).y = 17* scaleXY
Gp(17).x = 5.25 * scaleXY
Gp(17).y = 20* scaleXY
END SUB
SUB DrawBezier(BYVAL dt AS SINGLE, pt0 AS POINT, _
pt1 AS POINT, pt2 AS POINT, pt3 AS POINT)
LOCAL t,x0,y0,x1,y1 AS SINGLE
t = 0
x1 = pt0.x * (1 - t) ^ 3 + pt1.x * 3 * t * (1 - t) ^ 2 + _
pt2.x * 3 * t ^ 2 * (1 - t) + pt3.x * t ^ 3
y1 = pt0.y * (1 - t) ^ 3 + pt1.y * 3 * t * (1 - t) ^ 2 + _
pt2.y * 3 * t ^ 2 * (1 - t) + pt3.y * t ^ 3
t = t + dt
DO WHILE t < 1
x0 = x1 : y0 = y1
x1 = pt0.x * (1 - t) ^ 3 + pt1.x * 3 * t * (1 - t) ^ 2 + _
pt2.x * 3 * t ^ 2 * (1 - t) + pt3.x * t ^ 3
y1 = pt0.y * (1 - t) ^ 3 + pt1.y * 3 * t * (1 - t) ^ 2 + _
pt2.y * 3 * t ^ 2 * (1 - t) + pt3.y * t ^ 3
GRAPHIC LINE (x0, y0)-(x1, y1), %BLUE
t = t + dt
LOOP
' Connect to the final point.
t = 1
x0 = x1 : y0 = y1 : x1 = pt3.x : y1 = pt3.y
GRAPHIC LINE (x0, y0)-(x1, y1), %BLUE
END SUB
' varying these values of dt and Tension
' can smoothen the curves
SUB DrawCurves(BYVAL dt AS SINGLE, BYVAL tension AS SINGLE)
LOCAL control_scale AS SINGLE, i AS INTEGER
LOCAL pt,pt_before, pt_after, pt_after2 AS POINT
LOCAL Di, DiPlus1, p1, p2, p3, p4 AS POINT
GRAPHIC CLEAR
control_scale = CSNG(tension / 0.5 * 0.175)
FOR i = 0 TO UBOUND(Gp) - 1
pt_before = Gp(MAX(i - 1, 0))
pt = Gp(i)
pt_after = Gp(i + 1)
pt_after2 = Gp(MIN(i + 2, UBOUND(Gp)))
p1 = Gp(i)
p4 = Gp(i + 1)
Di.X = pt_after.X - pt_before.X
Di.Y = pt_after.Y - pt_before.Y
p2.X = pt.X + control_scale * Di.X
p2.Y = pt.Y + control_scale * Di.Y
DiPlus1.X = pt_after2.X - Gp(i).X
DiPlus1.Y = pt_after2.Y - Gp(i).Y
p3.X = pt_after.X - control_scale * DiPlus1.X
p3.Y = pt_after.Y - control_scale * DiPlus1.Y
DrawBezier dt, p1, p2, p3, p4
NEXT i
GRAPHIC REDRAW
END SUB
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