1、计算直线与水平轴X之间的夹角
angle_lx( : : Row1, Column1, Row2, Column2 : Angle)
角度计算方式：将直线看作向量（有方向性），以直线与水平轴的交点为起点（旋转中心）。如果终点在水平轴上方，则夹角为逆时针旋转水平轴到向量的角度（带正号）。如果终点在水平轴下方，则夹角为顺时针旋转水平轴到向量的角度（带负号）。结果取决于定义线条的两点的顺序。
角度表示方式：弧度，-π<=Angle<π
dev_close_window()
dev_open_window (0, 0, 512, 512, 'black', WindowHandle)
Row1 := 100
Col1 := 100
Row2 := 500
Col2 := 600
Row1Half := (Row1 + Row2)/2
Col1Half := (Col1 + Col2)/2
dev_set_color ('red')
gen_region_line (RegionLines, Row1, Col1, Row2, Col2)
gen_arrow_contour_xld (Arrow1, Row1Half, Col1Half, Row1, Col1, 25, 15)
dev_set_color ('yellow')
gen_region_line (ROI_0, 350, 100, 350, 750)
XRowHalf := 350
XColHalf := (100 + 700)/2
gen_arrow_contour_xld (Arrow, XRowHalf, XColHalf,350, 750, 25, 15)
angle_lx (Row2, Col2, Row1, Col1, Angle)
disp_message (WindowHandle, '红色线角度为：' + deg(Angle), 'window', 12, 12, 'black', 'true')
disp_message (WindowHandle, 'X', 'Image', 345, 765, 'yellow', 'false')
stop()
dev_clear_window()
Row1 := 100
Col1 := 100
Row2 := 500
Col2 := 600
Row1Half := (Row1 + Row2)/2
Col1Half := (Col1 + Col2)/2
dev_set_color ('red')
gen_region_line (RegionLines, Row1, Col1, Row2, Col2)
gen_arrow_contour_xld (Arrow1, Row1Half, Col1Half, Row2, Col2, 25, 15)
dev_set_color ('yellow')
gen_region_line (ROI_0, 350, 100, 350, 750)
XRowHalf := 350
XColHalf := (100 + 700)/2
gen_arrow_contour_xld (Arrow, XRowHalf, XColHalf,350, 750, 25, 15)
angle_lx (Row1, Col1,Row2, Col2, Angle)
disp_message (WindowHandle, '红色线角度为：' + deg(Angle), 'window', 12, 12, 'black', 'true')
disp_message (WindowHandle, 'X', 'Image', 345, 765, 'yellow', 'false')2、计算两条直线之间的夹角
angle_ll( : : RowA1, ColumnA1, RowA2, ColumnA2, RowB1, ColumnB1, RowB2, ColumnB2 : Angle)
角度计算方式：该算子计算原理与angle_lx类似，只不过把水平轴替换为任意直线B
角度表示方式：弧度，-π<=Angle<=π
dev_close_window()
dev_open_window (0, 0, 512, 512, 'black', WindowHandle)
set_display_font (WindowHandle, 26, 'mono', 'true', 'false')
Row1 := 100
Col1 := 100
Row2 := 500
Col2 := 600
Row1Half := (Row1 + Row2)/2
Col1Half := (Col1 + Col2)/2
Row3 := 400
Col3 := 100
Row4 := 100
Col4 := 500
Row2Half := (Row3 + Row4)/2
Col2Half := (Col3 + Col4)/2
dev_set_color ('red')
gen_region_line (RegionLines, Row1, Col1, Row2, Col2)
gen_arrow_contour_xld (Arrow1, Row1Half, Col1Half, Row1, Col1, 25, 15)
dev_set_color ('blue')
gen_region_line (RegionLines, Row3, Col3, Row4, Col4)
gen_arrow_contour_xld (Arrow1, Row2Half, Col2Half, Row3, Col3, 25, 15)
angle_ll (Row4, Col4,Row3, Col3, Row2, Col2,Row1, Col1, Angle)
disp_message (WindowHandle, '蓝色线转向红色线角度为：' + deg(Angle), 'window', 12, 12, 'black', 'true')
stop()
dev_clear_window()
Row1 := 100
Col1 := 100
Row2 := 500
Col2 := 600
Row1Half := (Row1 + Row2)/2
Col1Half := (Col1 + Col2)/2
Row3 := 400
Col3 := 100
Row4 := 100
Col4 := 500
Row2Half := (Row3 + Row4)/2
Col2Half := (Col3 + Col4)/2
dev_set_color ('red')
gen_region_line (RegionLines, Row1, Col1, Row2, Col2)
gen_arrow_contour_xld (Arrow1, Row1Half, Col1Half, Row1, Col1, 25, 15)
dev_set_color ('blue')
gen_region_line (RegionLines, Row3, Col3, Row4, Col4)
gen_arrow_contour_xld (Arrow1, Row2Half, Col2Half, Row4, Col4, 25, 15)
angle_ll (Row3, Col3, Row4, Col4, Row2, Col2,Row1, Col1, Angle)
disp_message (WindowHandle, '蓝色线转向红色线角度为：' + deg(Angle), 'window', 12, 12, 'black', 'true')
stop()
dev_clear_window()
Row1 := 100
Col1 := 100
Row2 := 500
Col2 := 600
Row1Half := (Row1 + Row2)/2
Col1Half := (Col1 + Col2)/2
Row5 := 250
Col5 := 20
Row6 := 250
Col6 := 550
Row3Half := (Row5 + Row6)/2
Col3Half := (Col5 + Col6)/2
dev_set_color ('red')
gen_region_line (RegionLines, Row1, Col1, Row2, Col2)
gen_arrow_contour_xld (Arrow1, Row1Half, Col1Half, Row1, Col1, 25, 15)
dev_set_color ('yellow')
gen_region_line (RegionLines, Row5, Col5, Row6, Col6)
gen_arrow_contour_xld (Arrow1, Row3Half, Col3Half, Row6, Col6, 25, 15)
angle_ll (Row2, Col2,Row1, Col1,Row5, Col5, Row6, Col6, Angle)
disp_message (WindowHandle, '红色线转向黄色色线角度为：' + deg(Angle), 'window', 12, 12, 'black', 'true')
stop()
dev_clear_window()
Row1 := 100
Col1 := 100
Row2 := 500
Col2 := 600
Row1Half := (Row1 + Row2)/2
Col1Half := (Col1 + Col2)/2
Row5 := 250
Col5 := 20
Row6 := 250
Col6 := 550
Row3Half := (Row5 + Row6)/2
Col3Half := (Col5 + Col6)/2
dev_set_color ('red')
gen_region_line (RegionLines, Row1, Col1, Row2, Col2)
gen_arrow_contour_xld (Arrow1, Row1Half, Col1Half, Row1, Col1, 25, 15)
dev_set_color ('yellow')
gen_region_line (RegionLines, Row5, Col5, Row6, Col6)
gen_arrow_contour_xld (Arrow1, Row3Half, Col3Half, Row6, Col6, 25, 15)
angle_ll (Row5, Col5, Row6, Col6, Row2, Col2,Row1, Col1, Angle)
disp_message (WindowHandle, '黄色线转向红色线角度为：' + deg(Angle), 'window', 12, 12, 'black', 'true')3、计算一条直线的方向
line_orientation( : : RowBegin, ColBegin, RowEnd, ColEnd : Phi)
角度计算方式：当直线（无方向性）大致位于1、3象限的方向，角度为正。当直线大致位于2、4象限的方向，角度为负。
角度表示方式：弧度，-π/2<Phi<=π/2
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参考文献