starting a new page
# File lib/pdf/reader/page_state.rb, line 22 def initialize(page) @page = page @cache = page.cache @objects = page.objects @font_stack = [build_fonts(page.fonts)] @xobject_stack = [page.xobjects] @cs_stack = [page.color_spaces] @stack = [DEFAULT_GRAPHICS_STATE.dup] end
Text Object Operators
# File lib/pdf/reader/page_state.rb, line 72 def begin_text_object @text_matrix = Matrix.identity(3) @text_line_matrix = Matrix.identity(3) end
update the current transformation matrix.
If the CTM is currently undefined, just store the new values.
If there's an existing CTM, then multiply the existing matrix with the new matrix to form the updated matrix.
# File lib/pdf/reader/page_state.rb, line 55 def concatenate_matrix(a, b, c, d, e, f) transform = Matrix[ [a, b, 0], [c, d, 0], [e, f, 1] ] if state[:ctm] state[:ctm] = transform * state[:ctm] else state[:ctm] = transform end end
transform x and y co-ordinates from the current user space to the underlying device space.
# File lib/pdf/reader/page_state.rb, line 199 def ctm_transform(x, y, z = 1) [ (ctm[0,0] * x) + (ctm[1,0] * y) + (ctm[2,0] * z), (ctm[0,1] * x) + (ctm[1,1] * y) + (ctm[2,1] * z) ] end
# File lib/pdf/reader/page_state.rb, line 217 def current_font find_font(state[:text_font]) end
# File lib/pdf/reader/page_state.rb, line 77 def end_text_object @text_matrix = Matrix.identity(3) @text_line_matrix = Matrix.identity(3) end
# File lib/pdf/reader/page_state.rb, line 228 def find_color_space(label) dict = @cs_stack.detect { |colorspaces| colorspaces.has_key?(label) } dict ? dict[label] : nil end
# File lib/pdf/reader/page_state.rb, line 221 def find_font(label) dict = @font_stack.detect { |fonts| fonts.has_key?(label) } dict ? dict[label] : nil end
# File lib/pdf/reader/page_state.rb, line 235 def find_xobject(label) dict = @xobject_stack.detect { |xobjects| xobjects.has_key?(label) } dict ? dict[label] : nil end
# File lib/pdf/reader/page_state.rb, line 99 def font_size state[:text_font_size] * @text_matrix[0,0] end
XObjects
# File lib/pdf/reader/page_state.rb, line 170 def invoke_xobject(label) save_graphics_state xobject = find_xobject(label) raise MalformedPDFError, "XObject #{label} not found" if xobject.nil? matrix = xobject.hash[:Matrix] concatenate_matrix(*matrix) if matrix if xobject.hash[:Subtype] == :Form form = PDF::Reader::FormXObject.new(@page, xobject, :cache => @cache) @font_stack.unshift(form.font_objects) @xobject_stack.unshift(form.xobjects) yield form if block_given? @font_stack.shift @xobject_stack.shift else yield xobject if block_given? end restore_graphics_state end
Text Positioning Operators
# File lib/pdf/reader/page_state.rb, line 123 def move_text_position(x, y) # Td temp_matrix = Matrix[ [1, 0, 0], [0, 1, 0], [x, y, 1] ] @text_matrix = @text_line_matrix = temp_matrix * @text_line_matrix end
# File lib/pdf/reader/page_state.rb, line 132 def move_text_position_and_set_leading(x, y) # TD set_text_leading(-1 * y) move_text_position(x, y) end
# File lib/pdf/reader/page_state.rb, line 157 def move_to_next_line_and_show_text(str) # ' move_to_start_of_next_line end
# File lib/pdf/reader/page_state.rb, line 145 def move_to_start_of_next_line # T* move_text_position(0, -state[:text_leading]) end
# File lib/pdf/reader/page_state.rb, line 40 def restore_graphics_state @stack.pop end
Graphics State Operators
# File lib/pdf/reader/page_state.rb, line 36 def save_graphics_state @stack.push clone_state end
Text State Operators
# File lib/pdf/reader/page_state.rb, line 86 def set_character_spacing(char_spacing) state[:char_spacing] = char_spacing end
# File lib/pdf/reader/page_state.rb, line 90 def set_horizontal_text_scaling(h_scaling) state[:h_scaling] = h_scaling end
# File lib/pdf/reader/page_state.rb, line 161 def set_spacing_next_line_show_text(aw, ac, string) # " set_word_spacing(aw) set_character_spacing(ac) move_to_next_line_and_show_text(string) end
# File lib/pdf/reader/page_state.rb, line 94 def set_text_font_and_size(label, size) state[:text_font] = label state[:text_font_size] = size end
# File lib/pdf/reader/page_state.rb, line 103 def set_text_leading(leading) state[:text_leading] = leading end
# File lib/pdf/reader/page_state.rb, line 137 def set_text_matrix_and_text_line_matrix(a, b, c, d, e, f) # Tm @text_matrix = @text_line_matrix = Matrix[ [a, b, 0], [c, d, 0], [e, f, 1] ] end
# File lib/pdf/reader/page_state.rb, line 107 def set_text_rendering_mode(mode) state[:text_mode] = mode end
# File lib/pdf/reader/page_state.rb, line 111 def set_text_rise(rise) state[:text_rise] = rise end
# File lib/pdf/reader/page_state.rb, line 115 def set_word_spacing(word_spacing) state[:word_spacing] = word_spacing end
Text Showing Operators
# File lib/pdf/reader/page_state.rb, line 153 def show_text_with_positioning(params) # TJ # TODO record position changes in state here end
transform x and y co-ordinates from the current text space to the underlying device space.
# File lib/pdf/reader/page_state.rb, line 209 def trm_transform(x, y, z = 1) trm = text_rendering_matrix [ (trm[0,0] * x) + (trm[1,0] * y) + (trm[2,0] * z), (trm[0,1] * x) + (trm[1,1] * y) + (trm[2,1] * z) ] end
when #save_graphics_state is called, we need to push a new copy of the current state onto the stack. That way any modifications to the state will be undone once #restore_graphics_state is called.
This returns a deep clone of the current state, ensuring changes are keep separate from earlier states.
Marshal is used to round-trip the state through a string to easily perform the deep clone. Kinda hacky, but effective.
# File lib/pdf/reader/page_state.rb, line 284 def clone_state if @stack.empty? {} else Marshal.load Marshal.dump(@stack.last) end end
return the current transformation matrix
# File lib/pdf/reader/page_state.rb, line 256 def ctm state[:ctm] end
# File lib/pdf/reader/page_state.rb, line 260 def state @stack.last end
# File lib/pdf/reader/page_state.rb, line 244 def text_rendering_matrix state_matrix = Matrix[ [font_size * state[:h_scaling], 0, 0], [0, font_size, 0], [0, state[:text_rise], 1] ] state_matrix * @text_matrix * ctm end