import curses import string from enum import IntEnum from bebop.colors import ColorPair from bebop.gemtext import (Blockquote, Link, ListItem, Paragraph, Preformatted, Title) SPLIT_CHARS = " \t-" JOIN_CHAR = "-" LIST_ITEM_MARK = "• " class LineType(IntEnum): """Type of line. Keep lines type along with the content for later rendering. Title type values match the title level to avoid looking it up. """ NONE = 0 TITLE_1 = 1 TITLE_2 = 2 TITLE_3 = 3 PARAGRAPH = 4 LINK = 5 PREFORMATTED = 6 BLOCKQUOTE = 7 LIST_ITEM = 8 def format_elements(elements, width): """Format elements into a list of lines with metadata. The returned list ("metalines") are tuples (meta, line), meta being a dict of metadata and line a text line to display. Currently the only metadata keys used are: - type: one of the Renderer.TYPE constants. - url: only for links, the URL the link on this line refers to. Note that this key is present only for the first line of the link, i.e. long link descriptions wrapped on multiple lines will not have a this key except for the first line. - link_id: only alongside "url" key, ID generated for this link. """ metalines = [] context = {"last_link_id": 0, "width": width} separator = ({"type": LineType.NONE}, "") has_margins = False for index, element in enumerate(elements): previous_had_margins = has_margins has_margins = False if isinstance(element, Title): element_metalines = format_title(element, context) has_margins = True elif isinstance(element, Paragraph): element_metalines = format_paragraph(element, context) has_margins = True elif isinstance(element, Link): element_metalines = format_link(element, context) elif isinstance(element, Preformatted): element_metalines = format_preformatted(element, context) has_margins = True elif isinstance(element, Blockquote): element_metalines = format_blockquote(element, context) has_margins = True elif isinstance(element, ListItem): element_metalines = format_list_item(element, context) else: continue # If current element requires margins and is not the first elements, # separate from previous element. Also do it if the current element does # not require margins but follows an element that required it (e.g. link # after a paragraph). if ( (has_margins and index > 0) or (not has_margins and previous_had_margins) ): metalines.append(separator) metalines += element_metalines return metalines def format_title(title: Title, context: dict): """Return metalines for this title.""" if title.level == 1: wrapped = wrap_words(title.text, context["width"]) line_template = f"{{:^{context['width']}}}" lines = (line_template.format(line) for line in wrapped) else: if title.level == 2: lines = wrap_words(title.text, context["width"], indent=2) else: lines = wrap_words(title.text, context["width"]) # Title levels match the type constants of titles. return [({"type": LineType(title.level)}, line) for line in lines] def format_paragraph(paragraph: Paragraph, context: dict): """Return metalines for this paragraph.""" lines = wrap_words(paragraph.text, context["width"]) return [({"type": LineType.PARAGRAPH}, line) for line in lines] def format_link(link: Link, context: dict): """Return metalines for this link.""" # Get a new link and build the "[id]" anchor. link_id = context["last_link_id"] + 1 context["last_link_id"] = link_id link_text = link.text or link.url link_anchor = f"[{link_id}] " # Wrap lines, indented by the link anchor length. lines = wrap_words(link_text, context["width"], indent=len(link_anchor)) first_line_meta = { "type": LineType.LINK, "url": link.url, "link_id": link_id } # Replace first line indentation with the anchor. first_line_text = link_anchor + lines[0][len(link_anchor):] first_line = [(first_line_meta, first_line_text)] other_lines = [({"type": LineType.LINK}, line) for line in lines[1:]] return first_line + other_lines def format_preformatted(preformatted: Preformatted, context: dict): """Return metalines for this preformatted block.""" return [ ({"type": LineType.PREFORMATTED}, line) for line in preformatted.lines ] def format_blockquote(blockquote: Blockquote, context: dict): """Return metalines for this blockquote.""" lines = wrap_words(blockquote.text, context["width"]) return [({"type": LineType.BLOCKQUOTE}, line) for line in lines] def format_list_item(item: ListItem, context: dict): """Return metalines for this list item.""" indent = len(LIST_ITEM_MARK) lines = wrap_words(item.text, context["width"], indent=indent) first_line = LIST_ITEM_MARK + lines[0][indent:] lines[0] = first_line return [({"type": LineType.LIST_ITEM}, line) for line in lines] def wrap_words(text, width, indent=0): """Wrap a text in several lines according to the renderer's width.""" lines = [] line = " " * indent words = _explode_words(text) for word in words: line_len, word_len = len(line), len(word) # If adding the new word would overflow the line, use a new line. if line_len + word_len > width: # Push only non-empty lines. if line_len > 0: lines.append(line) line = " " * indent # Force split words that are longer than the width. while word_len > width: split_offset = width - 1 - indent word_line = " " * indent + word[:split_offset] + JOIN_CHAR lines.append(word_line) word = word[split_offset:] word_len = len(word) word = word.lstrip() line += word if line: lines.append(line) return lines def _explode_words(text): words = [] pos = 0 while True: sep, sep_index = _find_next_sep(text[pos:]) if not sep: words.append(text[pos:]) return words word = text[pos : pos + sep_index] # If the separator is not a space char, append it to the word. if sep in string.whitespace: words.append(word) words.append(sep) else: words.append(word + sep) pos += sep_index + 1 def _find_next_sep(text): indices = [] for sep in SPLIT_CHARS: try: indices.append((sep, text.index(sep))) except ValueError: pass if not indices: return ("", 0) return min(indices, key=lambda e: e[1]) def render_lines(metalines, window, max_width): """Write a list of metalines in window. As this function does not know about the window/pad previous size, it expects a cleared window, especially if the new content is shorter than the previous one: merely clearing after the resize will not remove artefacts. Arguments: - metalines: list of metalines to render, must have at least one element. - window: window that will be resized as filled with rendered lines. - max_width: line length limit for the pad. Return: The tuple (height, width) of the resized window. """ num_lines = len(metalines) window.resize(num_lines, max_width) for line_index, metaline in enumerate(metalines): meta, line = metaline line = line[:max_width - 1] line_type = meta["type"] if line_type == LineType.TITLE_1: attr = curses.color_pair(ColorPair.TITLE_1) | curses.A_BOLD elif line_type == LineType.TITLE_2: attr = curses.color_pair(ColorPair.TITLE_2) | curses.A_BOLD elif line_type == LineType.TITLE_3: attr = curses.color_pair(ColorPair.TITLE_3) elif line_type == LineType.LINK: attr = curses.color_pair(ColorPair.LINK) elif line_type == LineType.PREFORMATTED: attr = curses.color_pair(ColorPair.PREFORMATTED) elif line_type == LineType.BLOCKQUOTE: attr = curses.color_pair(ColorPair.BLOCKQUOTE) | curses.A_ITALIC else: # includes LineType.PARAGRAPH attr = curses.color_pair(ColorPair.NORMAL) window.addstr(line, attr) if line_index < num_lines - 1: window.addstr("\n") return num_lines, max_width