//
// This code is part of GrapeCity Documents for Imaging samples.
// Copyright (c) GrapeCity, Inc. All rights reserved.
//
using System;
using System.IO;
using System.Drawing;
using GrapeCity.Documents.Drawing;
using GrapeCity.Documents.Imaging;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Html;
namespace GcImagingWeb.Samples
{
// This sample shows how to render a hard-coded HTML string.
//
// Adding GcHtml to your projects:
// - Public classes and extension methods that enable rendering HTML
// are provided by the GrapeCity.Documents.Html (GcHtml) package.
// - GcHtml supports Windows, macOS and Linux platforms.
//
// Dealing with errors when using GcHtml:
// - If GcHtml is not doing what you expect (e.g. rendering HTML to PDF
// produces an invalid PDF), check the content of the string property
// GcHtmlBrowser.ErrorLog after the call to SaveAsPdf returns,
// it may explain why the error occurred.
//
// GcHtml uses a local copy of a Chromium-based browser.
// You can either rely on Google Chrome or Microsoft Edge browsers
// installed in the operating system, or download an instance of
// Chromium browser to the application's local folder or some shared folder.
// If you know the custom path to an installed Chromium-based browser,
// use it instead of the above-mentioned options.
// The BrowserFetcher class can be used to install or fetch an already
// installed browser, you can then use the BrowserFetcher.GetDownloadedPath()
// to get the path to the browser. See the BrowserFetcher class for methods
// retrieving the path to Chrome or Edge executables and for other
// options and methods that help to download Chromium browser
// to a local folder if necessary.
//
// See the Util.NewHtmlBrowser() utility method used by this sample for a
// implementation example.
//
// The above notes apply to any project that uses GcHtml.
public class HelloWorldHtml
{
public GcBitmap GenerateImage(Size pixelSize, float dpi, bool opaque, string[] sampleParams = null)
{
// HTML code that represents the content to render:
var html = "<!DOCTYPE html>" +
"<html>" +
"<head>" +
"<style>" +
"span.bold {" +
"font-weight: bold;" +
"}" +
"p.round {" +
"font: 36px arial, sans-serif;" +
"color: DarkSlateBlue;" +
"border: 4px solid SlateBlue;" +
"border-radius: 16px;" +
"padding: 3px 5px 3px 5px;" +
"text-shadow: 3px 2px LightSkyBlue;" +
"}" +
"</style>" +
"</head>" +
"<body>" +
"<p class='round'>Hello, World, from <span class='bold'>GcHtml</span>!</p>" +
"</body>" +
"</html>";
var margin = dpi;
var bmp = new GcBitmap(pixelSize.Width, pixelSize.Height, true, dpi, dpi);
using (var g = bmp.CreateGraphics(Color.White))
{
// Create an instance of GcHtmlBrowser that is used to render HTML:
using var browser = Common.Util.NewHtmlBrowser();
// Render HTML.
// The return value from DrawHtml() indicates whether anything has been rendered.
// The output parameter 'size' returns the actual size of the rendered content.
var ok = g.DrawHtml(browser, html,
margin, margin,
new HtmlToImageFormat(true)
{
WindowSize = new Size((int)(pixelSize.Height - margin * 2), (int)(pixelSize.Width - margin * 2))
},
out SizeF size);
// If anything has been rendered, draw an extra border around the rendered content:
if (ok)
{
var rc = new RectangleF(margin - 4, margin - 4, size.Width + 8, size.Height + 8);
g.DrawRoundRect(rc, 8, Color.PaleVioletRed);
}
else if (!string.IsNullOrEmpty(browser.ErrorLog))
{
// Optional diagnostics that may be useful when diagnosing browser errors.
// Note that the error log may contain harmless information messages
// even if there were no errors, so testing whether the error log is empty
// should not be used as the error indicator.
Common.Util.AddNote(browser.ErrorLog, g,
new RectangleF(margin, margin + size.Height + 36, bmp.PixelWidth - margin * 2, bmp.PixelHeight - size.Height - margin * 2));
}
}
return bmp;
}
}
}