在gtk3/python中创建打印任务
我有一些信息（一个活动参与者的名单），我想简单地打印出来。没必要搞得太花哨，只要一个有几列的表格，如果能在每行文字之间加条线，那就更好了，这样看起来更清晰。为了让所有内容都能放下，我需要横向打印（可以通过GtkPageSetup来实现）。
我在用Python，操作系统是Linux，所以我得用GtkPrintUnixDialog这个接口。我在网上找了很久，但就是找不到任何关于怎么实现这个的例子。
为了简化问题：这只是我自己用，所以纸张大小是固定的（A4）。
我面临的主要问题有两个：1）创建一个格式正确的文本，适合打印，2）把这个文本发送到打印机。
有没有什么建议可以让我开始？或者更好的是，能不能给我一些完整的例子？
1 个回答
5
我在找我以前的打印示例，先说说基本的：
你可以把内容写到一个PDF表面上，然后打印这个PDF，或者把绘图代码放在一个叫on_print的函数里。需要注意的是，它打印的不是你看到的内容，而是你在打印表面上绘制的内容。你可以像使用普通的cairo上下文那样绘制，但有一些方法是不可用的（不适合打印上下文），而其他一些方法，比如新建页面，是可以用的。如果我找到示例代码，我会再给出一个更容易理解的答案。
编辑：找到了一个示例：
def on_button_clicked(self, widget):
ps = Gtk.PaperSize.new_custom("cc", "cc", 210, 297, Gtk.Unit.MM)
st = Gtk.PrintSettings()
s = Gtk.PageSetup()
s.set_paper_size(ps)
s.set_bottom_margin(4.3, Gtk.Unit.MM)
s.set_left_margin(4.3, Gtk.Unit.MM)
s.set_right_margin(4.3, Gtk.Unit.MM)
s.set_top_margin(4.3, Gtk.Unit.MM)
s.set_orientation(Gtk.PageOrientation.LANDSCAPE)
# ret = Gtk.print_run_page_setup_dialog(self, s, st)
pd = Gtk.PrintOperation()
pd.set_n_pages(1)
pd.set_default_page_setup(s)
pd.connect("begin_print", self.bg)
pd.connect("draw_page", self.draw_page)
# print(ret, s, st)
pd.set_export_filename("test.pdf")
result = pd.run(Gtk.PrintOperationAction.EXPORT, None) #play with action, but for test export first; if it's ok, then action.PRINT
print (result) # handle errors etc.
# Gtk.PaperSize.free(ps) - not needed in py
上面的代码可以在按钮按下时触发，或者其他事件。
def draw_page (self, operation, context, page_number):
end = self.layout.get_line_count()
cr = context.get_cairo_context()
cr.set_source_rgb(0, 0, 0)
i = 0
start = 0
start_pos = 0
iter = self.layout.get_iter()
while 1:
if i >= start:
line = iter.get_line()
print(line)
_, logical_rect = iter.get_line_extents()
# x_bearing, y_bearing, lwidth, lheight = logical_rect
baseline = iter.get_baseline()
if i == start:
start_pos = 12000 / 1024.0 # 1024.0 is float(pango.SCALE)
cr.move_to(0 / 1024.0, baseline / 1024.0 - start_pos)
PangoCairo.show_layout_line(cr, line)
i += 1
if not (i < end and iter.next_line()):
break
这只是一个基本示例。要注意，布局是一个pango布局：
self.layout = cx.create_pango_layout()
self.layout.set_width(int(w / 4 * Pango.SCALE))
self.layout.set_text(text, len(text))
num_lines = self.layout.get_line_count()
page_height = 0
self.layout.set_font_description(Pango.FontDescription("Georgia Bold 12"))
k = 0
for line in range(num_lines):
if k == 4:
self.layout.set_font_description(Pango.FontDescription("Georgia 10"))
layout_line = self.layout.get_line(line)
ink_rect, logical_rect = layout_line.get_extents()
lheight = 1200
line_height = lheight / 1024.0 # 1024.0 is float(pango.SCALE)
page_height += line_height
k += 1
print ("page_height ", page_height)
复制/粘贴的功能示例：
#!/usr/bin/python
from gi.repository import Gtk, Pango, PangoCairo
import cairo
text = '''
Text.
I have some information (a list of participants to an event) which I
want to print out easily.
No need for fancy layout,
just a table with several columns,
and if possible a drawn line in between the lines of
text for better readability.
'''
class MyWindow(Gtk.Window):
def __init__(self):
Gtk.Window.__init__(self, title="Hello World Printing")
self.button = Gtk.Button(label="Print A Rectangle")
self.button.connect("clicked", self.on_button_clicked)
self.add(self.button)
def on_button_clicked(self, widget):
ps = Gtk.PaperSize.new_custom("cc", "cc", 210, 297, Gtk.Unit.MM)
st = Gtk.PrintSettings()
s = Gtk.PageSetup()
s.set_paper_size(ps)
s.set_bottom_margin(4.3, Gtk.Unit.MM)
s.set_left_margin(4.3, Gtk.Unit.MM)
s.set_right_margin(4.3, Gtk.Unit.MM)
s.set_top_margin(4.3, Gtk.Unit.MM)
s.set_orientation(Gtk.PageOrientation.LANDSCAPE)
# ret = Gtk.print_run_page_setup_dialog(self, s, st)
pd = Gtk.PrintOperation()
pd.set_n_pages(1)
pd.set_default_page_setup(s)
pd.connect("begin_print", self.bg)
pd.connect("draw_page", self.draw_page)
# print(ret, s, st)
pd.set_export_filename("test.pdf")
result = pd.run(Gtk.PrintOperationAction.EXPORT, None)
print (result) # handle errors etc.
# Gtk.PaperSize.free(ps)
def bg(self, op, cx):
w = cx.get_width()
h = cx.get_height()
self.layout = cx.create_pango_layout()
self.layout.set_width(int(w / 4 * Pango.SCALE))
self.layout.set_text(text, len(text))
num_lines = self.layout.get_line_count()
page_height = 0
self.layout.set_font_description(Pango.FontDescription("Georgia Bold 12"))
k = 0
for line in range(num_lines):
if k == 4:
self.layout.set_font_description(Pango.FontDescription("Georgia 10"))
layout_line = self.layout.get_line(line)
ink_rect, logical_rect = layout_line.get_extents()
# print(logical_rect, ink_rect)
# x_bearing, y_bearing, lwidth, lheight = logical_rect
lheight = 1200
line_height = lheight / 1024.0 # 1024.0 is float(pango.SCALE)
page_height += line_height
# page_height is the current location on a page.
# It adds the the line height on each pass through the loop
# Once it is greater then the height supplied by context.get_height
# it marks the line and sets the current page height back to 0
k += 1
print ("page_height ", page_height)
def box(self, w, h, x, y, cx):
w, h = int(w), int(h)
cx.set_font_size(100)
cx.set_source_rgb(0, 0, 0)
cx.rectangle(x, y, w, h)
cx.stroke()
yy = 120
cx.select_font_face("Times", 0, 1)
ex = cx.text_extents("TEGOLA ROMÂNIA SRL")[2]
cx.move_to(w / 2 - ex / 2 + x, 105 + y)
cx.show_text("TEGOLA ROMÂNIA SRL")
ex = cx.text_extents("Str. Plevnei, nr. 5, Buzău")[2]
cx.move_to(w / 2 - ex / 2 + x, 210 + y)
cx.show_text("Str. Plevnei, nr. 5, Buzău")
ex = cx.text_extents("Tel.: 0238/710.280")[2]
cx.move_to(w / 2 - ex / 2 + x, 320 + y)
cx.show_text("Tel.: 0238/710.280")
ex = cx.text_extents("Fax : 0238/710021")[2]
cx.move_to(w / 2 - ex / 2 + x, 415 + y)
cx.show_text("Fax : 0238/710021")
cx.set_font_size(90)
cx.move_to(x + 120, 520 + y)
ex = cx.text_extents("Compoziție:")[2]
cx.show_text("Compoziție:")
cx.select_font_face("Times", 0, 0)
cx.move_to(x + 125 + ex, 520 + y)
cx.show_text("Polimer bituminos, liant și")
cx.move_to(x + 5, 620 + y)
cx.show_text("material de umplutură de înaltă calitate.")
cx.move_to(x + 5, 720 + y)
cx.show_text("Nu conține gudron.")
cx.move_to(x + 5, 800 + y)
cx.select_font_face("Times", 0, 1)
ex = cx.text_extents("Instrucțiuni de utilizare:")[2]
cx.show_text("Instrucțiuni de utilizare:")
cx.select_font_face("Times", 0, 0)
cx.move_to(x + 10 + ex, 800 + y)
cx.show_text("Suprafețele se")
def draw_page1(self, operation, context, page_nr=None):
ctx = context.get_cairo_context()
w = context.get_width()
h = context.get_height()
ww, hh = int(w / 4), int(h / 2)
self.k = 0
for x in range(2):
for y in range(4):
self.box(ww, hh, y * ww, x * hh, ctx)
self.k += 1
print(ctx.get_font_matrix())
def draw_page (self, operation, context, page_number):
end = self.layout.get_line_count()
cr = context.get_cairo_context()
cr.set_source_rgb(0, 0, 0)
i = 0
start = 0
start_pos = 0
iter = self.layout.get_iter()
while 1:
if i >= start:
line = iter.get_line()
print(line)
_, logical_rect = iter.get_line_extents()
# x_bearing, y_bearing, lwidth, lheight = logical_rect
baseline = iter.get_baseline()
if i == start:
start_pos = 12000 / 1024.0 # 1024.0 is float(pango.SCALE)
cr.move_to(0 / 1024.0, baseline / 1024.0 - start_pos)
PangoCairo.show_layout_line(cr, line)
i += 1
if not (i < end and iter.next_line()):
break
win = MyWindow()
win.connect("delete-event", Gtk.main_quit)
win.show_all()
Gtk.main()
别忘了把操作改成Gtk.PrintOperationAction.PRINT，这样才能真正进行打印。