module fortplot_pdf_mathtext_render !! PDF mathtext rendering utilities use, intrinsic :: iso_fortran_env, only: wp => real64 use fortplot_mathtext, only: mathtext_element_t, parse_mathtext, ELEMENT_SQRT use fortplot_latex_parser, only: process_latex_in_text use fortplot_pdf_core, only: pdf_context_core, PDF_LABEL_SIZE use fortplot_pdf_text_render, only: draw_mixed_font_text use fortplot_pdf_text_segments, only: render_mixed_font_at_position use fortplot_unicode, only: utf8_to_codepoint, utf8_char_length use fortplot_text_layout, only: preprocess_math_text use fortplot_pdf_text_metrics, only: estimate_pdf_text_width implicit none private public :: draw_pdf_mathtext public :: render_mathtext_element_pdf contains subroutine draw_pdf_mathtext(this, x, y, text, font_size) !! Draw text with mathematical notation class(pdf_context_core), intent(inout) :: this real(wp), intent(in) :: x, y character(len=*), intent(in) :: text real(wp), intent(in), optional :: font_size character(len=2048) :: preprocessed_text integer :: processed_len character(len=4096) :: math_ready integer :: mlen real(wp) :: fs fs = PDF_LABEL_SIZE if (present(font_size)) fs = font_size call process_latex_in_text(text, preprocessed_text, processed_len) call preprocess_math_text(preprocessed_text(1:processed_len), math_ready, mlen) call render_mathtext_with_unicode_superscripts(this, x, y, & math_ready(1:mlen), fs) end subroutine draw_pdf_mathtext subroutine render_mathtext_element_pdf(this, element, x_pos, baseline_y, & base_font_size) !! Render a single mathematical text element in PDF class(pdf_context_core), intent(inout) :: this type(mathtext_element_t), intent(in) :: element real(wp), intent(inout) :: x_pos real(wp), intent(in) :: baseline_y, base_font_size real(wp) :: elem_font_size, elem_y real(wp) :: char_width integer :: i, codepoint, char_len, text_len real(wp) :: sym_w, rad_width, top_y elem_font_size = base_font_size * element%font_size_ratio elem_y = baseline_y + element%vertical_offset * base_font_size ! Handle square root specially by drawing the radical (check mark + overbar) if (element%element_type == ELEMENT_SQRT) then ! Width of radical symbol and radicand sym_w = 0.6_wp * elem_font_size rad_width = estimate_pdf_text_width(element%text, elem_font_size) ! Place overbar slightly above baseline by approximately one font size top_y = baseline_y + elem_font_size ! Exit text object, draw path for radical, then re-enter text object this%stream_data = this%stream_data // 'ET' // new_line('a') ! Use current stroke settings; draw the two slanted ticks and horizontal bar block character(len=64) :: cmd cmd = to_move_cmd(x_pos, baseline_y) this%stream_data = this%stream_data // trim(adjustl(cmd)) // new_line('a') cmd = to_line_cmd(x_pos + sym_w/2.0_wp, baseline_y + sym_w/2.0_wp) this%stream_data = this%stream_data // trim(adjustl(cmd)) // new_line('a') cmd = to_line_cmd(x_pos + sym_w, top_y) this%stream_data = this%stream_data // trim(adjustl(cmd)) // new_line('a') cmd = to_line_cmd(x_pos + sym_w + rad_width, top_y) this%stream_data = this%stream_data // trim(adjustl(cmd)) // new_line('a') this%stream_data = this%stream_data // 'S' // new_line('a') end block ! Re-enter text mode for the radicand this%stream_data = this%stream_data // 'BT' // new_line('a') call render_mixed_font_at_position(this, x_pos + sym_w, elem_y, & element%text, elem_font_size) x_pos = x_pos + sym_w + rad_width return end if call render_mixed_font_at_position(this, x_pos, elem_y, element%text, & elem_font_size) char_width = 0.0_wp i = 1 ! Calculate width including trailing spaces by scanning beyond len_trim text_len = len_trim(element%text) do while (text_len < len(element%text)) if (element%text(text_len+1:text_len+1) == ' ') then text_len = text_len + 1 else exit end if end do do while (i <= text_len) char_len = utf8_char_length(element%text(i:i)) if (char_len == 0) then codepoint = iachar(element%text(i:i)) char_len = 1 else codepoint = utf8_to_codepoint(element%text, i) end if if (codepoint >= 48 .and. codepoint <= 57) then char_width = char_width + elem_font_size * 0.55_wp else if (codepoint >= 65 .and. codepoint <= 90) then char_width = char_width + elem_font_size * 0.65_wp else if (codepoint >= 97 .and. codepoint <= 122) then char_width = char_width + elem_font_size * 0.5_wp else if (codepoint == 32) then char_width = char_width + elem_font_size * 0.3_wp else if (codepoint >= 8304 .and. codepoint <= 8313) then char_width = char_width + elem_font_size * 0.4_wp else char_width = char_width + elem_font_size * 0.5_wp end if i = i + char_len end do x_pos = x_pos + char_width end subroutine render_mathtext_element_pdf subroutine render_mathtext_with_unicode_superscripts(this, x, y, text, font_size) class(pdf_context_core), intent(inout) :: this real(wp), intent(in) :: x, y character(len=*), intent(in) :: text real(wp), intent(in) :: font_size type(mathtext_element_t), allocatable :: elements(:) real(wp) :: x_pos integer :: i elements = parse_mathtext(text) this%stream_data = this%stream_data // 'BT' // new_line('a') x_pos = x do i = 1, size(elements) call render_mathtext_element_pdf(this, elements(i), x_pos, y, font_size) end do this%stream_data = this%stream_data // 'ET' // new_line('a') end subroutine render_mathtext_with_unicode_superscripts pure function to_move_cmd(x, y) result(cmd) real(wp), intent(in) :: x, y character(len=64) :: cmd write(cmd, '(F0.3,1X,F0.3,1X,A)') x, y, 'm' cmd = trim(adjustl(cmd)) end function to_move_cmd pure function to_line_cmd(x, y) result(cmd) real(wp), intent(in) :: x, y character(len=64) :: cmd write(cmd, '(F0.3,1X,F0.3,1X,A)') x, y, 'l' cmd = trim(adjustl(cmd)) end function to_line_cmd end module fortplot_pdf_mathtext_render