如何在Python / Curses子窗口中滚动文本?

时间:2010-03-25 12:04:54

标签: python scroll curses

在我使用Curses的Python脚本中,我有一个subwin,分配了一些文本。由于文本长度可能比窗口大小长,因此文本应该是可滚动的。

似乎没有像Curses窗口那样的CSS-“溢出”属性。在这方面,Python / Curses文档也相当神秘。

有没有人知道如何使用Python编写可滚动的Curses子窗口并实际滚动它?

\ edit:更准确的问题

6 个答案:

答案 0 :(得分:26)

使用window.scroll确定它太复杂了,无法移动窗口内容。相反,curses.newpad为我做了。

创建一个pad:

mypad = curses.newpad(40,60)
mypad_pos = 0
mypad.refresh(mypad_pos, 0, 5, 5, 10, 60)

然后你可以通过增加/减少mypad_pos来滚动,具体取决于cmd中window.getch()的输入:

if  cmd == curses.KEY_DOWN:
    mypad_pos += 1
    mypad.refresh(mypad_pos, 0, 5, 5, 10, 60)
elif cmd == curses.KEY_UP:
    mypad_pos -= 1
    mypad.refresh(mypad_pos, 0, 5, 5, 10, 60)

答案 1 :(得分:7)

是的,我对如何利用打击垫(为了滚动文本)感到有点困惑,在阅读这篇文章后仍然无法弄明白;特别是因为我想在内容为现有“行数组”的上下文中使用它。所以我准备了一个小例子,它显示newpadsubpad之间的相似性(和差异):

#!/usr/bin/env python2.7
import curses

# content - array of lines (list)
mylines = ["Line {0} ".format(id)*3 for id in range(1,11)]

import pprint
pprint.pprint(mylines)

def main(stdscr):
  hlines = begin_y = begin_x = 5 ; wcols = 10
  # calculate total content size
  padhlines = len(mylines)
  padwcols = 0
  for line in mylines:
    if len(line) > padwcols: padwcols = len(line)
  padhlines += 2 ; padwcols += 2 # allow border
  stdscr.addstr("padhlines "+str(padhlines)+" padwcols "+str(padwcols)+"; ")
  # both newpad and subpad are <class '_curses.curses window'>:
  mypadn = curses.newpad(padhlines, padwcols)
  mypads = stdscr.subpad(padhlines, padwcols, begin_y, begin_x+padwcols+4)
  stdscr.addstr(str(type(mypadn))+" "+str(type(mypads)) + "\n")
  mypadn.scrollok(1)
  mypadn.idlok(1)
  mypads.scrollok(1)
  mypads.idlok(1)
  mypadn.border(0) # first ...
  mypads.border(0) # ... border
  for line in mylines:
    mypadn.addstr(padhlines-1,1, line)
    mypadn.scroll(1)
    mypads.addstr(padhlines-1,1, line)
    mypads.scroll(1)
  mypadn.border(0) # second ...
  mypads.border(0) # ... border
  # refresh parent first, to render the texts on top
  #~ stdscr.refresh()
  # refresh the pads next
  mypadn.refresh(0,0, begin_y,begin_x, begin_y+hlines, begin_x+padwcols)
  mypads.refresh()
  mypads.touchwin()
  mypadn.touchwin()
  stdscr.touchwin() # no real effect here
  #stdscr.refresh() # not here! overwrites newpad!
  mypadn.getch()
  # even THIS command erases newpad!
  # (unless stdscr.refresh() previously):
  stdscr.getch()

curses.wrapper(main)

当你运行它时,首先你会得到(newpad左,subpad右):

 ┌────────────────────────┐    ┌────────────────────────┐
 │Line 1 Line 1 Line 1 ───│    │Line 1 Line 1 Line 1 ───│
 │Line 2 Line 2 Line 2    │    │Line 2 Line 2 Line 2    │
 │Line 3 Line 3 Line 3    │    │Line 3 Line 3 Line 3    │
 │Line 4 Line 4 Line 4    │    │Line 4 Line 4 Line 4    │
 │Line 5 Line 5 Line 5    │    │Line 5 Line 5 Line 5    │
                               │Line 6 Line 6 Line 6    │
                               │Line 7 Line 7 Line 7    │
                               │Line 8 Line 8 Line 8    │
                               │Line 9 Line 9 Line 9    │
                               │Line 10 Line 10 Line 10 │
                               └────────────────────────┘

一些注意事项:

  • newpadsubpad的宽度/高度应根据内容(num行/行数组的最大行宽)+最终边框空间
  • 在这两种情况下,您都可以允许额外的行scrollok() - 而不是额外的宽度
  • 在这两种情况下,你基本上都“推”了垫子底部的一条线;然后scroll()为下一个
  • 腾出空间
  • refresh所拥有的特殊newpad方法,只允许在屏幕上显示此“全部内容”的某个区域; subpad更多必须以
  • 中实例化的大小显示
  • 如果在添加内容字符串之前绘制打击垫的边框 - 那么边框也会向上滚动(即───部分显示的...Line 1 ───│部分)。

有用的链接:

答案 2 :(得分:2)

设置window.scrollok(True)。

Documentation

答案 3 :(得分:0)

这就是这个问题的答案: How to make a scrolling menu in python-curses

此代码允许您从字符串列表中的框中创建一个小滚动菜单。
您还可以使用此代码从sqlite查询或csv文件中获取字符串列表。
要编辑菜单的最大行数,您只需编辑max_row即可。
如果按Enter键,程序将打印所选字符串值及其位置。

from __future__ import division  #You don't need this in Python3
import curses
from math import *



screen = curses.initscr()
curses.noecho()
curses.cbreak()
curses.start_color()
screen.keypad( 1 )
curses.init_pair(1,curses.COLOR_BLACK, curses.COLOR_CYAN)
highlightText = curses.color_pair( 1 )
normalText = curses.A_NORMAL
screen.border( 0 )
curses.curs_set( 0 )
max_row = 10 #max number of rows
box = curses.newwin( max_row + 2, 64, 1, 1 )
box.box()


strings = [ "a", "b", "c", "d", "e", "f", "g", "h", "i", "l", "m", "n" ] #list of strings
row_num = len( strings )

pages = int( ceil( row_num / max_row ) )
position = 1
page = 1
for i in range( 1, max_row + 1 ):
    if row_num == 0:
        box.addstr( 1, 1, "There aren't strings", highlightText )
    else:
        if (i == position):
            box.addstr( i, 2, str( i ) + " - " + strings[ i - 1 ], highlightText )
        else:
            box.addstr( i, 2, str( i ) + " - " + strings[ i - 1 ], normalText )
        if i == row_num:
            break

screen.refresh()
box.refresh()

x = screen.getch()
while x != 27:
    if x == curses.KEY_DOWN:
        if page == 1:
            if position < i:
                position = position + 1
            else:
                if pages > 1:
                    page = page + 1
                    position = 1 + ( max_row * ( page - 1 ) )
        elif page == pages:
            if position < row_num:
                position = position + 1
        else:
            if position < max_row + ( max_row * ( page - 1 ) ):
                position = position + 1
            else:
                page = page + 1
                position = 1 + ( max_row * ( page - 1 ) )
    if x == curses.KEY_UP:
        if page == 1:
            if position > 1:
                position = position - 1
        else:
            if position > ( 1 + ( max_row * ( page - 1 ) ) ):
                position = position - 1
            else:
                page = page - 1
                position = max_row + ( max_row * ( page - 1 ) )
    if x == curses.KEY_LEFT:
        if page > 1:
            page = page - 1
            position = 1 + ( max_row * ( page - 1 ) )

    if x == curses.KEY_RIGHT:
        if page < pages:
            page = page + 1
            position = ( 1 + ( max_row * ( page - 1 ) ) )
    if x == ord( "\n" ) and row_num != 0:
        screen.erase()
        screen.border( 0 )
        screen.addstr( 14, 3, "YOU HAVE PRESSED '" + strings[ position - 1 ] + "' ON POSITION " + str( position ) )

    box.erase()
    screen.border( 0 )
    box.border( 0 )

    for i in range( 1 + ( max_row * ( page - 1 ) ), max_row + 1 + ( max_row * ( page - 1 ) ) ):
        if row_num == 0:
            box.addstr( 1, 1, "There aren't strings",  highlightText )
        else:
            if ( i + ( max_row * ( page - 1 ) ) == position + ( max_row * ( page - 1 ) ) ):
                box.addstr( i - ( max_row * ( page - 1 ) ), 2, str( i ) + " - " + strings[ i - 1 ], highlightText )
            else:
                box.addstr( i - ( max_row * ( page - 1 ) ), 2, str( i ) + " - " + strings[ i - 1 ], normalText )
            if i == row_num:
                break



    screen.refresh()
    box.refresh()
    x = screen.getch()

curses.endwin()
exit()

答案 4 :(得分:0)

我想使用滚动键盘来显示一些大型文本文件的内容,但这并不好用,因为文本可以有换行符,很难弄清楚一次显示多少个字符适合很多列和行。

所以我决定首先将我的文本文件拆分成精确的COLUMNS字符行,当行太短时用空格填充。然后滚动文本变得更加容易。

以下是显示任何文本文件的示例代码:

#!/usr/bin/python
# -*- coding: utf-8 -*-

import curses
import locale
import sys

def main(filename, filecontent, encoding="utf-8"):
    try:
        stdscr = curses.initscr()
        curses.noecho()
        curses.cbreak()
        curses.curs_set(0)
        stdscr.keypad(1)
        rows, columns = stdscr.getmaxyx()
        stdscr.border()
        bottom_menu = u"(↓) Next line | (↑) Previous line | (→) Next page | (←) Previous page | (q) Quit".encode(encoding).center(columns - 4)
        stdscr.addstr(rows - 1, 2, bottom_menu, curses.A_REVERSE)
        out = stdscr.subwin(rows - 2, columns - 2, 1, 1)
        out_rows, out_columns = out.getmaxyx()
        out_rows -= 1
        lines = map(lambda x: x + " " * (out_columns - len(x)), reduce(lambda x, y: x + y, [[x[i:i+out_columns] for i in xrange(0, len(x), out_columns)] for x in filecontent.expandtabs(4).splitlines()]))
        stdscr.refresh()
        line = 0
        while 1:
            top_menu = (u"Lines %d to %d of %d of %s" % (line + 1, min(len(lines), line + out_rows), len(lines), filename)).encode(encoding).center(columns - 4)
            stdscr.addstr(0, 2, top_menu, curses.A_REVERSE)
            out.addstr(0, 0, "".join(lines[line:line+out_rows]))
            stdscr.refresh()
            out.refresh()
            c = stdscr.getch()
            if c == ord("q"):
                break
            elif c == curses.KEY_DOWN:
                if len(lines) - line > out_rows:
                    line += 1
            elif c == curses.KEY_UP:
                if line > 0:
                    line -= 1
            elif c == curses.KEY_RIGHT:
                if len(lines) - line >= 2 * out_rows:
                    line += out_rows
            elif c == curses.KEY_LEFT:
                if line >= out_rows:
                    line -= out_rows
    finally:
        curses.nocbreak(); stdscr.keypad(0); curses.echo(); curses.curs_set(1)
        curses.endwin()

if __name__ == '__main__':
    locale.setlocale(locale.LC_ALL, '')
    encoding = locale.getpreferredencoding()
    try:
        filename = sys.argv[1]
    except:
        print "Usage: python %s FILENAME" % __file__
    else:
        try:
            with open(filename) as f:
                filecontent = f.read()
        except:
            print "Unable to open file %s" % filename
        else:
            main(filename, filecontent, encoding)

主要技巧是这一行:

lines = map(lambda x: x + " " * (out_columns - len(x)), reduce(lambda x, y: x + y, [[x[i:i+out_columns] for i in xrange(0, len(x), out_columns)] for x in filecontent.expandtabs(4).splitlines()]))

首先,文本中的表格被转换为空格,然后我使用splitlines()方法将我的文本转换为行数组。 但是有些行可能比我们的COLUMNS数字长,所以我将COLUMNS字符块中的每一行拆分,然后使用reduce来在行列表中转换结果列表。 最后,我使用map用尾随空格填充每一行,使其长度正好是COLUMNS字符。

希望这有帮助。

答案 5 :(得分:0)

另一种方法是使用带有切片符号的列表上的 for 循环打印可见项。也就是说,您选择要显示的列表的特定部分,然后每次向上或向下按一个键时增加或减少一个增量以更改范围。
比如flutter_svg,其中y 是开头,coverage 决定了您要在列表中显示多少项。 >

list[ y : y + coverage ]