Convert PDF to image (JPG, PNG, BMP, TIFF) in Ruby

#---------------------------------------------------------------------------------------
# Copyright (c) 2001-2022 by PDFTron Systems Inc. All Rights Reserved.
# Consult LICENSE.txt regarding license information.
#---------------------------------------------------------------------------------------

require '../../../PDFNetC/Lib/PDFNetRuby'
include PDFNetRuby
require '../../LicenseKey/RUBY/LicenseKey'

$stdout.sync = true

# Relative path to the folder containing test files.
input_path =  "../../TestFiles/"
output_path = "../../TestFiles/Output/"

#---------------------------------------------------------------------------------------
# The following sample illustrates how to convert PDF documents to various raster image 
# formats (such as PNG, JPEG, BMP, TIFF, etc), as well as how to convert a PDF page to 
# GDI+ Bitmap for further manipulation and/or display in WinForms applications.
#---------------------------------------------------------------------------------------

	# The first step in every application using PDFNet is to initialize the 
	# library and set the path to common PDF resources. The library is usually 
	# initialized only once, but calling Initialize multiple times is also fine.
	PDFNet.Initialize(PDFTronLicense.Key)
	
	# Optional: Set ICC color profiles to fine tune color conversion 
	# for PDF 'device' color spaces...

	# PDFNet.SetResourcesPath("../../../resources")
	# PDFNet.SetColorManagement
	# PDFNet.SetDefaultDeviceCMYKProfile("D:/Misc/ICC/USWebCoatedSWOP.icc")
	# PDFNet.SetDefaultDeviceRGBProfile("AdobeRGB1998.icc") # will search in PDFNet resource folder.

	# ----------------------------------------------------
	# Optional: Set predefined font mappings to override default font 
	# substitution for documents with missing fonts...

	# PDFNet.AddFontSubst("StoneSans-Semibold", "C:/WINDOWS/Fonts/comic.ttf")
	# PDFNet.AddFontSubst("StoneSans", "comic.ttf")  # search for 'comic.ttf' in PDFNet resource folder.
	# PDFNet.AddFontSubst(PDFNet.E_Identity, "C:/WINDOWS/Fonts/arialuni.ttf")
	# PDFNet.AddFontSubst(PDFNet.E_Japan1, "C:/Program Files/Adobe/Acrobat 7.0/Resource/CIDFont/KozMinProVI-Regular.otf")
	# PDFNet.AddFontSubst(PDFNet.E_Japan2, "c:/myfonts/KozMinProVI-Regular.otf")
	# PDFNet.AddFontSubst(PDFNet.E_Korea1, "AdobeMyungjoStd-Medium.otf")
	# PDFNet.AddFontSubst(PDFNet.E_CNS1, "AdobeSongStd-Light.otf")
	# PDFNet.AddFontSubst(PDFNet.E_GB1, "AdobeMingStd-Light.otf")
	
	#Example 1) Convert the first page to PNG and TIFF at 92 DPI.
	
	# PDFDraw class is used to rasterize PDF pages.
	draw = PDFDraw.new
	
	#--------------------------------------------------------------------------------
	# Example 1) Convert the first page to PNG and TIFF at 92 DPI. 
	# A three step tutorial to convert PDF page to an image.
	
	# A) Open the PDF document.
	doc = PDFDoc.new(input_path + "tiger.pdf")
	
	# Initialize the security handler, in case the PDF is encrypted.
	doc.InitSecurityHandler
	
	# B) The output resolution is set to 92 DPI.
	draw.SetDPI(92)
	
	# C) Rasterize the first page in the document and save the result as PNG.
	itr = doc.GetPageIterator
	draw.Export(itr.Current, output_path + "tiger_92dpi.png")
	
	puts "Example 1: tiger_92dpi.png"
	
	# Export the same page as TIFF
	itr = doc.GetPageIterator
	draw.Export(itr.Current, (output_path + "tiger_92dpi.tif"), "TIFF")
	
	#--------------------------------------------------------------------------------
	# Example 2) Convert the all pages in a given document to JPEG at 72 DPI.

	puts "Example 2:"
	
	hint_set = ObjSet.new # A collection of rendering 'hits'.
	
	doc = PDFDoc.new(input_path + "newsletter.pdf")
	# Initialize the security handler, in case the PDF is encrypted.
	doc.InitSecurityHandler
	
	# Set the output resolution is to 72 DPI.
	draw.SetDPI(72)
	
	# Use optional encoder parameter to specify JPEG quality.
	encoder_param = hint_set.CreateDict
	encoder_param.PutNumber("Quality", 80)
	
	# Traverse all pages in the document.
	itr = doc.GetPageIterator
	while itr.HasNext do
		filename = "newsletter" + itr.Current.GetIndex.to_s + ".jpg"
		puts filename
		draw.Export(itr.Current, output_path + filename, "JPEG", encoder_param)
		itr.Next
	end
	puts "Done."

	# Examples 3-5
	# Common code for remaining samples.
	tiger_doc = PDFDoc.new(input_path + "tiger.pdf")
	# Initialize the security handler, in case the PDF is encrypted.
	tiger_doc.InitSecurityHandler
	page = tiger_doc.GetPage(1)
	
	#--------------------------------------------------------------------------------
	# Example 3) Convert the first page to raw bitmap. Also, rotate the 
	# page 90 degrees and save the result as RAW.
	draw.SetDPI(100)	# Set the output resolution is to 100 DPI.
	draw.SetRotate(Page::E_90)   # Rotate all pages 90 degrees clockwise.
	bmp = draw.GetBitmap(page, PDFDraw::E_rgb)

	# Save the raw RGB data to disk.
	File.open(output_path + "tiger_100dpi_rot90.raw", 'w') { |file| file.write(bmp.GetBuffer) }
	
	puts "Example 3: tiger_100dpi_rot90.raw"
	
	draw.SetRotate(Page::E_0)	# Disable image rotation for remaining samples.
	
	#--------------------------------------------------------------------------------
	# Example 4) Convert PDF page to a fixed image size. Also illustrates some 
	# other features in PDFDraw class such as rotation, image stretching, exporting 
	# to grayscale, or monochrome.
	
	# Initialize render 'gray_hint' parameter, that is used to control the 
	# rendering process. In this case we tell the rasterizer to export the image as 
	# 1 Bit Per Component (BPC) image.
	mono_hint = hint_set.CreateDict
	mono_hint.PutNumber("BPC", 1)
	
	# SetImageSize can be used instead of SetDPI to adjust page scaling
	# dynamically so that given image fits into a buffer of given dimensions.
	draw.SetImageSize(1000, 1000)   # Set the output image to be 1000 wide and 1000 pixels tall
	draw.Export(page, output_path + "tiger_1000x1000.png", "PNG", mono_hint)
	puts "Example 4: tiger_1000x1000.png"
	
	draw.SetImageSize(200, 400)	 # Set the output image to be 200 wide and 400 pixels tall
	draw.SetRotate(Page::E_180)	 # Rotate all pages 90 degrees clockwise
	
	# 'gray_hint' tells the rasterizer to export the image as grayscale.
	gray_hint = hint_set.CreateDict
	gray_hint.PutName("ColorSpace", "Gray")
	
	draw.Export(page, (output_path + "tiger_200x400_rot180.png"), "PNG", gray_hint)
	puts "Example 4: tiger_200x400_rot180.png"
	
	draw.SetImageSize(400, 200, false)  # The third parameter sets 'preserve-aspect-ratio' to false
	draw.SetRotate(Page::E_0)	 # Disable image rotation
	draw.Export(page, output_path + "tiger_400x200_stretch.jpg", "JPEG")
	puts "Example 4: tiger_400x200_stretch.jpg"
	
	#--------------------------------------------------------------------------------
	# Example 5) Zoom into a specific region of the page and rasterize the 
	# area at 200 DPI and as a thumbnail (i.e. a 50x50 pixel image).
	zoom_rect = Rect.new(216, 522, 330, 600)
	page.SetCropBox(zoom_rect)	# Set the page crop box.

	# Select the crop region to be used for drawing.
	draw.SetPageBox(Page::E_crop)
	draw.SetDPI(900)  # Set the output image resolution to 900 DPI.
	draw.Export(page, output_path + "tiger_zoom_900dpi.png", "PNG")
	puts "Example 5: tiger_zoom_900dpi.png"

	# -------------------------------------------------------------------------------
	# Example 6)
	draw.SetImageSize(50, 50)	# Set the thumbnail to be 50x50 pixel image.
	draw.Export(page, output_path + "tiger_zoom_50x50.png", "PNG")
	puts "Example 6: tiger_zoom_50x50.png"

	cmyk_hint = hint_set.CreateDict
	cmyk_hint.PutName("ColorSpace", "CMYK")
	
	#--------------------------------------------------------------------------------
	# Example 6) Convert the first PDF page to CMYK TIFF at 92 DPI.
	# A three step tutorial to convert PDF page to an image
	# A) Open the PDF document
	doc = PDFDoc.new(input_path + "tiger.pdf")
	# Initialize the security handler, in case the PDF is encrypted.
	doc.InitSecurityHandler
	
	# The output resolution is set to 92 DPI.
	draw.SetDPI(92)
	
	# C) Rasterize the first page in the document and save the result as TIFF.
	pg = doc.GetPage(1)
	draw.Export(pg, output_path + "out1.tif", "TIFF", cmyk_hint)
	puts "Example 7: out1.tif"
		
	doc.Close

	# A) Open the PDF document.
	doc = PDFDoc.new(input_path + "tiger.pdf")
	# Initialize the security handler, in case the PDF is encrypted.
	doc.InitSecurityHandler  

	# B) Get the page matrix 
	pg = doc.GetPage(1)
	box = Page::E_crop
	mtx = pg.GetDefaultMatrix(true, box)
	# We want to render a quadrant, so use half of width and height
	pg_w = pg.GetPageWidth(box) / 2
	pg_h = pg.GetPageHeight(box) / 2

	# C) Scale matrix from PDF space to buffer space
	dpi = 96.0
	scale = dpi / 72.0 # PDF space is 72 dpi
	buf_w = ((scale * pg_w).floor).to_i
	buf_h = ((scale * pg_h).floor).to_i
	bytes_per_pixel = 4 # BGRA buffer
	buf_size = buf_w * buf_h * bytes_per_pixel
	mtx.Translate(0, -pg_h) # translate by '-pg_h' since we want south-west quadrant
	mtx = Matrix2D.new(scale, 0, 0, scale, 0, 0).Multiply(mtx)

	# D) Rasterize page into memory buffer, according to our parameters
	rast = PDFRasterizer.new
	buf = rast.Rasterize(pg, buf_w, buf_h, buf_w * bytes_per_pixel, bytes_per_pixel, true, mtx)

	# buf now contains raw BGRA bitmap.
	puts "Example 8: Successfully rasterized into memory buffer."

	#--------------------------------------------------------------------------------
	# Example 9) Export raster content to PNG using different image smoothing settings. 
	text_doc = PDFDoc.new(input_path + "lorem_ipsum.pdf")
	text_doc.InitSecurityHandler

	draw.SetImageSmoothing(false, false)
	filename = "raster_text_no_smoothing.png"
	draw.Export(text_doc.GetPageIterator.Current, output_path + filename)
	puts "Example 9 a): " + filename + ". Done."

	filename = "raster_text_smoothed.png"
	# default quality bilinear resampling
	draw.SetImageSmoothing(true, false)
	draw.Export(text_doc.GetPageIterator.Current, output_path + filename)
	puts "Example 9 b): " + filename + ". Done."

	filename = "raster_text_high_quality.png"
	# high quality area resampling
	draw.SetImageSmoothing(true, true)
	draw.Export(text_doc.GetPageIterator.Current, output_path + filename)
	puts "Example 9 c): " + filename + ". Done."

	#--------------------------------------------------------------------------------
	# Example 10) Export separations directly, without conversion to an output colorspace

	separation_doc = PDFDoc.new(input_path + "op_blend_test.pdf")
	separation_doc.InitSecurityHandler
	separation_hint = hint_set.CreateDict
	separation_hint.PutName("ColorSpace", "Separation")
	draw.SetDPI(96)
	draw.SetImageSmoothing(true, true)
	draw.SetOverprint(PDFRasterizer::E_op_on)

	filename = "merged_separations.png"
	draw.Export(separation_doc.GetPageIterator.Current, output_path + filename, "PNG")
	puts "Example 10 a): " + filename + ". Done."

	filename = "separation"
	draw.Export(separation_doc.GetPageIterator.Current, output_path + filename, "PNG", separation_hint)
	puts "Example 10 b): " + filename + "_[ink].png. Done."

	filename = "separation_NChannel.tif"
	draw.Export(separation_doc.GetPageIterator.Current, output_path + filename, "TIFF", separation_hint)
	puts "Example 10 c): " + filename + ". Done."
	PDFNet.Terminate