HelloWorldHtml.cs
//
// 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 allow to render HTML
// are provided by the GrapeCity.Documents.Html (GcHtml) package.
// - GcHtml supports Windows, macOS and Linux platforms.
// - Internally, it uses one of 3 system-dependent HTML engine packages:
// -- GrapeCity.Documents.Html.Windows.X64
// -- GrapeCity.Documents.Html.Mac.X64
// -- GrapeCity.Documents.Html.Linux.X64
// - GcHtml will automatically select the correct system-dependent engine package
// at runtime, but that package must be referenced by your project so that GcHtml
// can find it. You can add references to all 3 platform packages to your project,
// or if you only target one or two platforms, you can add just the packages for
// these target platforms.
//
// Dealing with errors when using GcHtml:
// - If GcHtml is not doing what you expect (e.g. rendering HTML to an image
// produces empty or corrupted images) - check the content of the static string property
// GcHtmlRenderer.LastLogMessage after the call to GcHtml returns,
// it may explain why the error occurred (e.g. a required shared library
// might be missing on Linux).
// - Sometimes the HTML rendering process can hang without any diagnostics
// being written to GcHtmlRenderer.LastLogMessage. GcHtml automatically kills
// the hanging process in this case, but there is no diagnostics.
// Normally such situations should not occur.
//
// The above notes apply to any project that uses GcHtml.
public class HelloWorldHtml
{
public GcBitmap GenerateImage(int pixelWidth = 1024, int pixelHeight = 1024, bool opaque = true, float dpiX = 96, float dpiY = 96)
{
// 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 = dpiX;
var bmp = new GcBitmap(pixelWidth, pixelHeight, true, dpiX, dpiY);
using (var g = bmp.CreateGraphics(Color.White))
{
// 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(html,
margin, margin,
new HtmlToImageFormat(true)
{
WindowSize = new Size((int)(pixelHeight - margin * 2), (int)(pixelWidth - 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);
}
// Optional diagnostics that may help in case of unexpected behavior
// (do NOT leave such code in production, as the last log message might
// contain harmless messages even if all is ok):
/*
var tf = new TextFormat
{
Font = Font.FromFile(Path.Combine("Resources", "Fonts", "timesbd.ttf")),
FontSize = 14,
ForeColor = Color.OrangeRed,
};
var rcDiag = new RectangleF(0, 0, pixelWidth, pixelHeight);
if (!string.IsNullOrEmpty(GcHtmlRenderer.LastLogMessage))
g.DrawString(GcHtmlRenderer.LastLogMessage, tf, rcDiag, TextAlignment.Center, ParagraphAlignment.Center, false);
else
g.DrawString("GcHtmlRenderer did not say anything", tf, rcDiag, TextAlignment.Center, ParagraphAlignment.Center, false);
*/
}
return bmp;
}
}
}