grotateを使えば画像を傾けたりすることが出来ます
詳細はHSPDocsLibraryで調べてみてください
一応単純な画像ならスクリプトのみでも描写可能です
#module
;太線描写
#deffunc hline int ex,int ey,int sx,int sy,int r
if r<=1{
line ex,ey,sx,sy
}else{
inter=atan(ey-sy,ex-sx)
xinter=sin(inter)*r
yinter=cos(inter)*r
dim xdata,4:xdata=sx+xinter,ex+xinter,ex-xinter,sx-xinter
dim ydata,4:ydata=sy-yinter,ey-yinter,ey+yinter,sy+yinter
gsquare -1,xdata,ydata
}
return
#global
;初期設定
gw=320
gwh=gw/2
gh=320
ghh=gh/2
rotradh=45
kjnrad0=deg2rad(270-rotradh)
kjnrad1=kjnrad0+deg2rad(90)
kjnrad2=kjnrad0+deg2rad(-270/2)
thickness=8
interval=thickness*4
screen ,gw,gh
;描写
repeat
color 255,255,255:boxf:color
r=deg2rad(cos(deg2rad(cnt*2))*rotradh)
lsx=cos(kjnrad0+r)*gw+gwh
lsy=sin(kjnrad0+r)*gw+ghh
rsx=cos(kjnrad1+r)*gw+gwh
rsy=sin(kjnrad1+r)*gw+ghh
repeat gh/(thickness*2)
hline lsx,lsy,rsx,rsy,thickness
lsx+=cos(kjnrad2+r)*interval
lsy+=sin(kjnrad2+r)*interval
rsx+=cos(kjnrad2+r)*interval
rsy+=sin(kjnrad2+r)*interval
loop
redraw
await 16
redraw 0
loop