# -*- encoding: utf-8; frozen_string_literal: true -*-
#
#--
# This file is part of HexaPDF.
#
# HexaPDF - A Versatile PDF Creation and Manipulation Library For Ruby
# Copyright (C) 2014-2019 Thomas Leitner
#
# HexaPDF is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License version 3 as
# published by the Free Software Foundation with the addition of the
# following permission added to Section 15 as permitted in Section 7(a):
# FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
# THOMAS LEITNER, THOMAS LEITNER DISCLAIMS THE WARRANTY OF NON
# INFRINGEMENT OF THIRD PARTY RIGHTS.
#
# HexaPDF is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
# License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with HexaPDF. If not, see .
#
# The interactive user interfaces in modified source and object code
# versions of HexaPDF must display Appropriate Legal Notices, as required
# under Section 5 of the GNU Affero General Public License version 3.
#
# In accordance with Section 7(b) of the GNU Affero General Public
# License, a covered work must retain the producer line in every PDF that
# is created or manipulated using HexaPDF.
#
# If the GNU Affero General Public License doesn't fit your need,
# commercial licenses are available at .
#++
require 'hexapdf/layout/style'
module HexaPDF
module Layout
# The base class for all layout boxes.
#
# HexaPDF uses the following box model:
#
# * Each box can specify a width and height. Padding and border are inside, the margin outside
# of this rectangle.
#
# * The #content_width and #content_height accessors can be used to get the width and height of
# the content box without padding and the border.
#
# * If width or height is set to zero, they are determined automatically during layouting.
class Box
# Creates a new Box object, using the provided block as drawing block (see ::new). Any
# additional keyword arguments are used for creating the box's Style object.
#
# If +content_box+ is +true+, the width and height are taken to mean the content width and
# height and the style's padding and border are removed from them appropriately.
def self.create(width: 0, height: 0, content_box: false, **style, &block)
style = Style.new(**style)
if content_box
width += style.padding.left + style.padding.right +
style.border.width.left + style.border.width.right
height += style.padding.top + style.padding.bottom +
style.border.width.top + style.border.width.bottom
end
new(width: width, height: height, style: style, &block)
end
# The width of the box, including padding and/or borders.
attr_reader :width
# The height of the box, including padding and/or borders.
attr_reader :height
# The style to be applied.
#
# Only the following properties are used:
#
# * Style#background_color
# * Style#padding
# * Style#border
# * Style#overlay_callback
# * Style#underlay_callback
attr_reader :style
# :call-seq:
# Box.new(width: 0, height: 0, style: Style.new) {|canv, box| block} -> box
#
# Creates a new Box object with the given width and height that uses the provided block when
# it is asked to draw itself on a canvas (see #draw).
#
# Since the final location of the box is not known beforehand, the drawing operations inside
# the block should draw inside the rectangle (0, 0, content_width, content_height) - note that
# the width and height of the box may not be known beforehand.
def initialize(width: 0, height: 0, style: Style.new, &block)
@width = @initial_width = width
@height = @initial_height = height
@style = (style.kind_of?(Style) ? style : Style.new(**style))
@draw_block = block
end
# The width of the content box, i.e. without padding and/or borders.
def content_width
width = @width - reserved_width
width < 0 ? 0 : width
end
# The height of the content box, i.e. without padding and/or borders.
def content_height
height = @height - reserved_height
height < 0 ? 0 : height
end
# Fits the box into the Frame and returns +true+ if fitting was successful.
#
# The default implementation uses the whole available space for width and height if they were
# initially set to 0. Otherwise the specified dimensions are used.
def fit(available_width, available_height, _frame)
@width = (@initial_width > 0 ? @initial_width : available_width)
@height = (@initial_height > 0 ? @initial_height : available_height)
@width <= available_width && @height <= available_height
end
# Tries to split the box into two, the first of which needs to fit into the available space,
# and returns the parts as array.
#
# In many cases the first box in the list will be this box, meaning that even when #fit fails,
# a part of the box may still fit. Note that #fit may not be called if the first box is this
# box since it is assumed that it is already fitted. If not even a part of this box fits into
# the available space, +nil+ should be returned as the first array element.
#
# Possible return values:
#
# [self]:: The box fully fits into the available space.
# [nil, self]:: The box can't be split or no part of the box fits into the available space.
# [self, new_box]:: A part of the box fits and a new box is returned for the rest.
#
# This default implementation provides no splitting functionality.
def split(_available_width, _available_height, _frame)
[nil, self]
end
# Draws the content of the box onto the canvas at the position (x, y).
#
# The coordinate system is translated so that the origin is at the bottom left corner of the
# **content box** during the drawing operations.
#
# The block specified when creating the box is invoked with the canvas and the box as
# arguments. Subclasses can specify an on-demand drawing method by setting the +@draw_block+
# instance variable to +nil+ or a valid block. This is useful to avoid unnecessary set-up
# operations when the block does nothing.
def draw(canvas, x, y)
if style.background_color? && style.background_color
canvas.save_graphics_state do
canvas.fill_color(style.background_color).rectangle(x, y, width, height).fill
end
end
style.underlays.draw(canvas, x, y, self) if style.underlays?
style.border.draw(canvas, x, y, width, height) if style.border?
cx = x
cy = y
(cx += style.padding.left; cy += style.padding.bottom) if style.padding?
(cx += style.border.width.left; cy += style.border.width.bottom) if style.border?
draw_content(canvas, cx, cy)
style.overlays.draw(canvas, x, y, self) if style.overlays?
end
# Returns +true+ if no drawing operations are performed.
def empty?
!(@draw_block ||
(style.background_color? && style.background_color) ||
(style.underlays? && !style.underlays.none?) ||
(style.border? && !style.border.none?) ||
(style.overlays? && !style.overlays.none?))
end
private
# Returns the width that is reserved by the padding and border style properties.
def reserved_width
result = 0
result += style.padding.left + style.padding.right if style.padding?
result += style.border.width.left + style.border.width.right if style.border?
result
end
# Returns the height that is reserved by the padding and border style properties.
def reserved_height
result = 0
result += style.padding.top + style.padding.bottom if style.padding?
result += style.border.width.top + style.border.width.bottom if style.border?
result
end
# Draws the content of the box at position [x, y] which is the bottom-left corner of the
# content box.
def draw_content(canvas, x, y)
if @draw_block
canvas.translate(x, y) { @draw_block.call(canvas, self) }
end
end
end
end
end