From 7aa1e5dd3d80e2664eac7eb0a409829e9785a521 Mon Sep 17 00:00:00 2001 From: Přemysl Eric Janouch Date: Wed, 8 Jan 2025 10:54:40 +0100 Subject: WIP: Add a Lua PDF generator Because Lua compiled for C++ might be hard to find, provide a wrap. Only GitHub releases seem to contain onelua.c, which is a very handy file. WIP: Add documentation, actually get rid of the libqr copy. --- lpg/lpg.lua | 165 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 lpg/lpg.lua (limited to 'lpg/lpg.lua') diff --git a/lpg/lpg.lua b/lpg/lpg.lua new file mode 100644 index 0000000..07ee44a --- /dev/null +++ b/lpg/lpg.lua @@ -0,0 +1,165 @@ +#!/usr/bin/env lpg +function h1 (title) + return lpg.VBox {fontsize=18., fontweight=600, + title, lpg.HLine {2}, lpg.Filler {-1, 6}} +end +function h2 (title) + return lpg.VBox {fontsize=16., fontweight=600, + lpg.Filler {-1, 8}, title, lpg.HLine {1}, lpg.Filler {-1, 4}} +end +function h3 (title) + return lpg.VBox {fontsize=14., fontweight=600, + lpg.Filler {-1, 8}, title, lpg.HLine {.25}, lpg.Filler {-1, 4}} +end +function p (...) + return lpg.VBox {..., lpg.Filler {-1, 6}} +end +function pre (...) + return lpg.VBox { + lpg.Filler {-1, 4}, + lpg.HBox {lpg.Filler {12}, lpg.VBox {...}, lpg.Filler {}}, + lpg.Filler {-1, 6}, + } +end +function define (name, ...) + return lpg.VBox { + lpg.Filler {-1, 2}, + lpg.Text {fontweight=600, name}, lpg.Filler {-1, 2}, + lpg.HBox {lpg.Filler {12}, lpg.VBox {...}, lpg.Filler {}}, + lpg.Filler {-1, 2}, + } +end + +local page1 = lpg.VBox {fontfamily="sans serif", fontsize=12., + h1("lpg User Manual"), + p("lpg is a Lua-based PDF document generator, exposing a trivial " .. + "layouting engine on top of the Cairo graphics library, " .. + "with manual paging."), + p("The author has primarily been using this system to typeset invoices."), + + h2("Synopsis"), + p("lpg program.lua [args...]"), + + h2("API"), + p("The Lua program receives lpg's and its own path joined " .. + "as arg[0]. Any remaining sequential elements " .. + "of this table represent the passed args."), + + h3("Utilities"), + + define("lpg.cm (centimeters)", + p("Returns how many document points are needed " .. + "for the given physical length.")), + + define("lpg.ntoa {number [, precision=…]\n" .. + "\t[, thousands_sep=…] [, decimal_point=…] [, grouping=…]}", + p("Formats a number using the C++ localization " .. + "and I/O libraries. " .. + "For example, the following call results in “3 141,59”:"), + pre("ntoa {3141.592, precision=2,\n" .. + " thousands_sep=\" \", decimal_point=\",\", " .. + "grouping=\"\\003\"}")), + + define("lpg.escape (values...)", + p("Interprets all values as strings, " .. + "and escapes them to be used as literal text—" .. + "all text within lpg is parsed Pango markup, " .. + "which is a subset of XML.")), + + h3("PDF documents"), + + define("lpg.Document (filename, width, height [, margin])", + p("Returns a new Document object, whose pages are all " .. + "the same size in 72 DPI points, as specified by width " .. + "and height. The margin is used by show " .. + "on all sides of pages."), + p("The file is finalized when the object is garbage collected.")), + + define("Document.title, author, subject, keywords, " .. + "creator, create_date, mod_date", + p("Write-only PDF Info dictionary metadata strings.")), + + define("Document:show ([widget...])", + p("Starts a new document page, and renders Widget trees over " .. + "the whole print area.")), + + lpg.Filler {}, +} + +local page2 = lpg.VBox {fontfamily="sans serif", fontsize=12., + h3("Widgets"), + p("The layouting system makes heavy use of composition, " .. + "and thus stays simple."), + p("For convenience, anywhere a Widget is expected but another " .. + "kind of value is received, lpg.Text widget will be invoked " .. + "on that value."), + p("Once a Widget is included in another Widget, " .. + "the original Lua object can no longer be used, " .. + "as its reference has been consumed."), + p("Widgets can be indexed by strings to get or set " .. + "their attributes. All Widget constructor tables " .. + "also accept attributes, for convenience. Attributes can be " .. + "either strings or numbers, mostly only act " .. + "on specific Widget kinds, and are hereditary. " .. + "Prefix their names with an underscore to set them ‘privately’."), + p("Widget sizes can be set negative, which signals to their " .. + "container that they should take any remaining space, " .. + "after all their siblings’ requests have been satisfied. " .. + "When multiple widgets make this request, that space is distributed " .. + "in proportion to these negative values."), + + define("lpg.Filler {[width] [, height]}", + p("Returns a new blank widget with the given dimensions, " .. + "which default to -1, -1.")), + define("lpg.HLine {[thickness]}", + p("Returns a new widget that draws a simple horizontal line " .. + "of the given thickness.")), + define("lpg.VLine {[thickness]}", + p("Returns a new widget that draws a simple vertical line " .. + "of the given thickness.")), + define("lpg.Text {[value...]}", + p("Returns a new text widget that renders the concatenation of all " .. + "passed values filtered through Lua’s tostring function."), + define("Text.fontfamily, fontsize, fontweight, lineheight", + p("Various font properties, similar to their CSS counterparts."))), + define("lpg.Frame {widget}", + p("Returns a special container widget that can override " .. + "a few interesting properties."), + define("Frame.color", + p("Text and line colour, for example 0xff0000 for red.")), + define("Frame.w_override", + p("Forcefully changes the child Widget’s " .. + "requested width, such as to negative values.")), + define("Frame.h_override", + p("Forcefully changes the child Widget’s " .. + "requested height, such as to negative values."))), + + lpg.Filler {}, +} + +local page3 = lpg.VBox {fontfamily="sans serif", fontsize=12., + -- TODO: Link + -- TODO: HBox + -- TODO: VBox + -- TODO: Picture + -- TODO: QR + + lpg.Filler {}, +} + +if #arg < 1 then + io.stderr:write("Usage: " .. arg[0] .. " OUTPUT-PDF..." .. "\n") + os.exit(false) +end +local width, height, margin = lpg.cm(21), lpg.cm(29.7), lpg.cm(2.0) +for i = 1, #arg do + local pdf = lpg.Document(arg[i], width, height, margin) + pdf.title = "lpg User Manual" + pdf.subject = "lpg User Manual" + pdf.author = "Přemysl Eric Janouch" + pdf.creator = "lpg" + + pdf:show(page1) + pdf:show(page2) + pdf:show(page3) +end -- cgit v1.2.3-70-g09d2