module fortplot_pdf_io !! PDF file I/O operations !! Handles PDF document structure, writing, and file management use iso_fortran_env, only: wp => real64 use fortplot_pdf_core, only: pdf_context_core use, intrinsic :: iso_fortran_env, only: int8 use fortplot_zlib_core, only: zlib_compress_into use fortplot_logging, only: log_error implicit none private ! Public procedures public :: write_pdf_file public :: create_pdf_document public :: write_string_to_unit public :: write_binary_to_unit ! PDF structure constants integer, parameter :: PDF_VERSION_OBJ = 1 integer, parameter :: PDF_CATALOG_OBJ = 2 integer, parameter :: PDF_PAGES_OBJ = 3 integer, parameter :: PDF_PAGE_OBJ = 4 integer, parameter :: PDF_HELVETICA_OBJ = 5 integer, parameter :: PDF_SYMBOL_OBJ = 6 integer, parameter :: PDF_CONTENT_OBJ = 7 integer, parameter :: PDF_IMAGE_OBJ = 8 contains subroutine write_pdf_file(this, filename, success) !! Write PDF context to file class(pdf_context_core), intent(inout) :: this character(len=*), intent(in) :: filename logical, intent(out), optional :: success integer :: unit, ios if (present(success)) success = .false. ! Open file for writing open(newunit=unit, file=filename, status='replace', & form='formatted', action='write', iostat=ios) if (ios /= 0) then call log_error('pdf_io: failed to open file for writing: ' // trim(filename)) if (present(success)) then return ! Return with success = .false. else return end if end if ! Write PDF document call create_pdf_document(unit, filename, this) ! Close file close(unit) if (present(success)) success = .true. end subroutine write_pdf_file subroutine create_pdf_document(unit, filename, ctx) !! Create complete PDF document structure integer, intent(in) :: unit character(len=*), intent(in) :: filename ! Placeholder for future use type(pdf_context_core), intent(inout) :: ctx ! Reference unused argument to keep interface stable associate(unused_fn_len => len_trim(filename)); end associate ! Write PDF header write(unit, '(A)') '%PDF-1.4' write(unit, '(A)') '%'//char(128)//char(129)//char(130)//char(131) ! Write PDF structure call write_pdf_structure(unit, ctx) end subroutine create_pdf_document subroutine write_pdf_structure(unit, ctx) !! Write complete PDF structure with all objects integer, intent(in) :: unit type(pdf_context_core), intent(in) :: ctx integer, allocatable :: positions(:) integer :: xref_pos ! Allocate position tracking array allocate(positions(8)) positions = 0 ! Write all objects and track positions call write_all_objects(unit, ctx, positions) ! Write cross-reference table and trailer call write_xref_and_trailer(unit, positions, xref_pos) end subroutine write_pdf_structure subroutine write_all_objects(unit, ctx, positions) !! Write all PDF objects integer, intent(in) :: unit type(pdf_context_core), intent(in) :: ctx integer, intent(inout) :: positions(:) ! Write catalog object call write_catalog_object(unit, positions(PDF_CATALOG_OBJ)) ! Write pages object call write_pages_object(unit, ctx, positions(PDF_PAGES_OBJ)) ! Write page object call write_page_object(unit, ctx, positions(PDF_PAGE_OBJ)) ! Write font objects call write_helvetica_font_object(unit, positions(PDF_HELVETICA_OBJ)) call write_symbol_font_object(unit, positions(PDF_SYMBOL_OBJ)) ! Write image XObject if present if (ctx%has_image) then call write_image_object(unit, ctx, positions(PDF_IMAGE_OBJ)) end if ! Write content stream object call write_content_object(unit, ctx, positions(PDF_CONTENT_OBJ)) end subroutine write_all_objects subroutine write_xref_and_trailer(unit, positions, xref_pos) !! Write cross-reference table and trailer integer, intent(in) :: unit integer, intent(in) :: positions(:) integer, intent(out) :: xref_pos integer :: i, num_objects num_objects = size(positions) ! Get current position for xref inquire(unit=unit, pos=xref_pos) ! Write xref header write(unit, '(A)') 'xref' write(unit, '(A, I0, 1X, I0)') '0 ', num_objects + 1 ! Write xref entries write(unit, '(A)') '0000000000 65535 f' do i = 1, num_objects write(unit, '(I10.10, A)') positions(i), ' 00000 n' end do ! Write trailer write(unit, '(A)') 'trailer' write(unit, '(A)') '<<' write(unit, '(A, I0)') '/Size ', num_objects + 1 write(unit, '(A, I0, A)') '/Root ', PDF_CATALOG_OBJ, ' 0 R' write(unit, '(A)') '>>' write(unit, '(A)') 'startxref' write(unit, '(I0)') xref_pos write(unit, '(A)') '%%EOF' end subroutine write_xref_and_trailer subroutine write_catalog_object(unit, pos) !! Write PDF catalog object integer, intent(in) :: unit integer, intent(out) :: pos inquire(unit=unit, pos=pos) write(unit, '(I0, A)') PDF_CATALOG_OBJ, ' 0 obj' write(unit, '(A)') '<<' write(unit, '(A)') '/Type /Catalog' write(unit, '(A, I0, A)') '/Pages ', PDF_PAGES_OBJ, ' 0 R' write(unit, '(A)') '>>' write(unit, '(A)') 'endobj' end subroutine write_catalog_object subroutine write_pages_object(unit, ctx, pos) !! Write PDF pages object integer, intent(in) :: unit type(pdf_context_core), intent(in) :: ctx integer, intent(out) :: pos ! Reference ctx to keep interface stable associate(unused_w => ctx%width); end associate inquire(unit=unit, pos=pos) write(unit, '(I0, A)') PDF_PAGES_OBJ, ' 0 obj' write(unit, '(A)') '<<' write(unit, '(A)') '/Type /Pages' write(unit, '(A, I0, A)') '/Kids [', PDF_PAGE_OBJ, ' 0 R]' write(unit, '(A)') '/Count 1' write(unit, '(A)') '>>' write(unit, '(A)') 'endobj' end subroutine write_pages_object subroutine write_page_object(unit, ctx, pos) !! Write PDF page object integer, intent(in) :: unit type(pdf_context_core), intent(in) :: ctx integer, intent(out) :: pos inquire(unit=unit, pos=pos) write(unit, '(I0, A)') PDF_PAGE_OBJ, ' 0 obj' write(unit, '(A)') '<<' write(unit, '(A)') '/Type /Page' write(unit, '(A, I0, A)') '/Parent ', PDF_PAGES_OBJ, ' 0 R' write(unit, '(A, F0.1, 1X, F0.1, A)') '/MediaBox [0 0 ', ctx%width, ctx%height, ']' write(unit, '(A)') '/Resources <<' write(unit, '(A)') ' /Font <<' write(unit, '(A, I0, A, I0, A)') ' /F', PDF_HELVETICA_OBJ, ' ', PDF_HELVETICA_OBJ, ' 0 R' write(unit, '(A, I0, A, I0, A)') ' /F', PDF_SYMBOL_OBJ, ' ', PDF_SYMBOL_OBJ, ' 0 R' write(unit, '(A)') ' >>' if (ctx%has_image) then write(unit, '(A)') ' /XObject <<' write(unit, '(A, I0, A)') ' /Im1 ', PDF_IMAGE_OBJ, ' 0 R' write(unit, '(A)') ' >>' end if write(unit, '(A)') '>>' write(unit, '(A, I0, A)') '/Contents ', PDF_CONTENT_OBJ, ' 0 R' write(unit, '(A)') '>>' write(unit, '(A)') 'endobj' end subroutine write_page_object subroutine write_image_object(unit, ctx, pos) integer, intent(in) :: unit type(pdf_context_core), intent(in) :: ctx integer, intent(out) :: pos integer :: n inquire(unit=unit, pos=pos) write(unit, '(I0, A)') PDF_IMAGE_OBJ, ' 0 obj' write(unit, '(A)') '<<' write(unit, '(A)') '/Type /XObject' write(unit, '(A)') '/Subtype /Image' write(unit, '(A, I0)') '/Width ', ctx%image_width write(unit, '(A, I0)') '/Height ', ctx%image_height write(unit, '(A)') '/ColorSpace /DeviceRGB' write(unit, '(A)') '/BitsPerComponent 8' write(unit, '(A)') '/Interpolate false' n = len(ctx%image_data) write(unit, '(A, I0)') '/Length ', n write(unit, '(A)') '/Filter /FlateDecode' write(unit, '(A)') '>>' write(unit, '(A)') 'stream' call write_binary_to_unit(unit, ctx%image_data, n) write(unit, '(A)') '' write(unit, '(A)') 'endstream' write(unit, '(A)') 'endobj' end subroutine write_image_object subroutine write_content_object(unit, ctx, pos) !! Write PDF content stream object integer, intent(in) :: unit type(pdf_context_core), intent(in) :: ctx integer, intent(out) :: pos integer :: stream_len ! Flate (zlib) compression buffers integer(int8), allocatable :: in_bytes(:) integer(int8), allocatable :: out_bytes(:) integer :: out_len integer :: i, n character(len=:), allocatable :: compressed_str stream_len = len_trim(ctx%stream_data) inquire(unit=unit, pos=pos) write(unit, '(I0, A)') PDF_CONTENT_OBJ, ' 0 obj' write(unit, '(A)') '<<' if (stream_len > 0) then allocate(in_bytes(stream_len)) do i = 1, stream_len in_bytes(i) = int(iachar(ctx%stream_data(i:i)), int8) end do call zlib_compress_into(in_bytes, stream_len, out_bytes, out_len) ! Build a character buffer from compressed bytes n = out_len compressed_str = repeat(' ', n) do i = 1, n compressed_str(i:i) = achar(iand(int(out_bytes(i), kind=4), 255)) end do write(unit, '(A, I0)') '/Length ', n write(unit, '(A)') '/Filter /FlateDecode' else write(unit, '(A, I0)') '/Length ', stream_len end if write(unit, '(A)') '>>' write(unit, '(A)') 'stream' ! Write the actual (possibly compressed) stream data if (stream_len > 0) then call write_binary_to_unit(unit, compressed_str, len(compressed_str)) else call write_string_to_unit(unit, ctx%stream_data) end if write(unit, '(A)') '' write(unit, '(A)') 'endstream' write(unit, '(A)') 'endobj' end subroutine write_content_object subroutine write_helvetica_font_object(unit, pos) !! Write Helvetica font object integer, intent(in) :: unit integer, intent(out) :: pos inquire(unit=unit, pos=pos) write(unit, '(I0, A)') PDF_HELVETICA_OBJ, ' 0 obj' write(unit, '(A)') '<<' write(unit, '(A)') '/Type /Font' write(unit, '(A)') '/Subtype /Type1' write(unit, '(A)') '/BaseFont /Helvetica' write(unit, '(A)') '/Encoding /WinAnsiEncoding' write(unit, '(A)') '>>' write(unit, '(A)') 'endobj' end subroutine write_helvetica_font_object subroutine write_symbol_font_object(unit, pos) !! Write Symbol font object integer, intent(in) :: unit integer, intent(out) :: pos inquire(unit=unit, pos=pos) write(unit, '(I0, A)') PDF_SYMBOL_OBJ, ' 0 obj' write(unit, '(A)') '<<' write(unit, '(A)') '/Type /Font' write(unit, '(A)') '/Subtype /Type1' write(unit, '(A)') '/BaseFont /Symbol' write(unit, '(A)') '>>' write(unit, '(A)') 'endobj' end subroutine write_symbol_font_object subroutine write_string_to_unit(unit, str) !! Write string to unit, handling long strings properly integer, intent(in) :: unit character(len=*), intent(in) :: str integer :: i, chunk_size integer :: str_len str_len = len_trim(str) chunk_size = 1000 ! Write in chunks to avoid line length issues ! Write string in chunks do i = 1, str_len, chunk_size if (i + chunk_size - 1 <= str_len) then write(unit, '(A)', advance='no') str(i:i+chunk_size-1) else write(unit, '(A)', advance='no') str(i:str_len) end if end do end subroutine write_string_to_unit subroutine write_binary_to_unit(unit, str, nbytes) !! Write binary string to unit using exact length (no trimming) integer, intent(in) :: unit character(len=*), intent(in) :: str integer, intent(in) :: nbytes integer :: i, chunk_size, last chunk_size = 1000 if (nbytes <= 0) return i = 1 do while (i <= nbytes) last = min(nbytes, i + chunk_size - 1) write(unit, '(A)', advance='no') str(i:last) i = last + 1 end do end subroutine write_binary_to_unit end module fortplot_pdf_io