【issue-halcon例程学习】median_interactive.hdev

例程功能

 对鼠标交互做出反应

代码如下

dev_set_preferences ('graphics_window_context_menu', 'false')
dev_close_window ()
dev_update_off ()
 1. ****
 2. step: acquire image
 3. ****
read_image (Image, 'mreut')
get_image_size (Image, Width, Height)
dev_open_window_fit_image (Image, 0, 0, Width, Height, WindowHandle)
set_display_font (WindowHandle, 12, 'mono', 'true', 'false')
dev_set_draw ('margin')
dev_set_line_width (3)
dev_display (Image)
disp_continue_message (WindowHandle, 'black', 'true')
stop ()
get_window_param (WindowHandle, 'flush', Flush)
set_window_param (WindowHandle, 'flush', 'false')
 4. ****
 5. step: react to mouse
 6. ****
Button := 0
while (Button != 4)
    Row := -1
    Column := -1
    dev_set_check ('~give_error')
    get_mposition (WindowHandle, Row, Column, Button)
    dev_set_check ('give_error')
    dev_display (Image)
    set_tposition (WindowHandle, Height - 40, 4)
    * check if mouse cursor is over window
    if (Row >= 0 and Column >= 0)
        gen_circle (Circle, Row, Column, 20)
        boundary (Circle, RegionBorder, 'inner')
        dev_display (RegionBorder)
        write_string (WindowHandle, 'Hold down mouse button to apply filter')
        if (Button == 1)
            * apply filter to circle if left button is pressed
            reduce_domain (Image, Circle, ImageReduced)
            median_image (ImageReduced, ImageMedian, 'circle', 5, 'mirrored')
            overpaint_gray (Image, ImageMedian)
        endif
    else
        write_string (WindowHandle, 'Please move mouse cursor over window')
    endif
    flush_buffer (WindowHandle)
endwhile
dev_display (Image)
set_window_param (WindowHandle, 'flush', Flush)

要点

1. get_mposition ——返回WindowHandle中鼠标指针和按下鼠标按钮的像素精确图像坐标；无鼠标点击则Button(返回参数)置0，鼠标左击置1，鼠标右击置4；
   set_tposition——设置文本光标的位置；
2. 从WindowHandle中获取Row、Column和Button，由Row和Column生成处理区域，由Button决定是否处理。代码中使用median_image 对选中区域进行反应。

    get_mposition (WindowHandle, Row, Column, Button) //WindowHandle已根据Image的w，h生成
	gen_circle (Circle, Row, Column, 20)
	reduce_domain (Image, Circle, ImageReduced) //Image已读
    median_image (ImageReduced, ImageMedian, 'circle', 5, 'mirrored')
    overpaint_gray (Image, ImageMedian)  //将区域中给定区域以固定灰度值绘制到图像中

3. 当WindowHandle的参数flush默认设置为true；
   设置为false时，所有显示操作(disp_obj/disp_text…)都重定向到缓冲区，对 WindowHandle 没有影响，flush_buffer 会将缓存内容传给WindowHandle。

	get_window_param (WindowHandle, 'flush', Flush)
	set_window_param (WindowHandle, 'flush', 'false')
	……
    flush_buffer (WindowHandle)