MergeRows.vb 
  1. ''
  2. '' This code is part of Document Solutions for Imaging demos.
  3. '' Copyright (c) MESCIUS inc. All rights reserved.
  4. ''
  5. Imports System.IO
  6. Imports System.Drawing
  7. Imports System.Text
  8. Imports System.Data
  9. Imports System.Linq
  10. Imports System.Collections.Generic
  11. Imports GrapeCity.Documents.Drawing
  12. Imports GrapeCity.Documents.Imaging
  13. Imports GrapeCity.Documents.Text
  14. Imports GrapeCity.Documents.Html
  15.  
  16. '' This sample shows how to build and render a table-based report
  17. '' grouped by the first column, with that column's cells with same
  18. '' values merged.
  19. '' This sample uses a JavaScript code in the HTML to actually
  20. '' merge the cells, demonstrating the use of JavaScript when
  21. '' rendering HTML to images.
  22. '' Note that the sample limits the number of rows so that
  23. '' the whole table fits in the image.
  24. ''
  25. '' Please see notes in comments at the top of HelloWorldHtml
  26. '' sample code for details on adding DsHtml to your projects.
  27. Public Class MergeRows
  28.     Function GenerateImageStream(
  29.                 ByVal targetMime As String,
  30.                 ByVal pixelSize As Size,
  31.                 ByVal dpi As Single,
  32.                 ByVal opaque As Boolean,
  33.                 Optional sampleParams As String() = Nothing) As Stream
  34.  
  35.         Const TTAG = "___TABLE___"
  36.  
  37.         '' HTML page template
  38.         Const tableTpl =
  39.             "<!DOCTYPE html>" +
  40.             "<html>" +
  41.             "<head>" +
  42.             "<style>" +
  43.             "" +
  44.             "html * {" +
  45.             "  font-family: 'Trebuchet MS', Arial, Helvetica, sans-serif !important;" +
  46.             "}" +
  47.             "" +
  48.             "h1 {" +
  49.             "  color: #1a5276;" +
  50.             "  background-color: #d2b4de;" +
  51.             "  text-align: center;" +
  52.             "  padding: 6px;" +
  53.             "}" +
  54.             "" +
  55.             "thead {display: table-header-group;}" +
  56.             "" +
  57.             "#products {" +
  58.             "  font-family: 'Trebuchet MS', Arial, Helvetica, sans-serif;" +
  59.             "  border-collapse: collapse;" +
  60.             "  width: 100%;" +
  61.             "}" +
  62.             "" +
  63.             "#products td, #products th {" +
  64.             "  border: 1px solid #ddd;" +
  65.             "  padding: 8px;" +
  66.             "}" +
  67.             "" +
  68.             "#products tr:hover {background-color: #ddd;}" +
  69.             "" +
  70.             "#products th {" +
  71.             "  padding-top: 12px;" +
  72.             "  padding-bottom: 12px;" +
  73.             "  text-align: left;" +
  74.             "  background-color: #a569bd;" +
  75.             "  color: white;" +
  76.             "}" +
  77.             "</style>" +
  78.             "" +
  79.             "</head>" +
  80.             "<body onload='mergeRows()'>" +
  81.             "" +
  82.             "<script>" +
  83.             "function mergeRows() {" +
  84.             "  const table = document.querySelector('table');" +
  85.             "  let headerCell = null;" +
  86.             "  for (let row of table.rows)" +
  87.             "  {" +
  88.             "    const firstCell = row.cells[0];" +
  89.             "    if (headerCell === null || firstCell.innerText !== headerCell.innerText)" +
  90.             "    {" +
  91.             "      headerCell = firstCell;" +
  92.             "    }" +
  93.             "    else" +
  94.             "    {" +
  95.             "      headerCell.rowSpan++;" +
  96.             "      firstCell.remove();" +
  97.             "    }" +
  98.             "  }" +
  99.             "}" +
  100.             "</script>" +
  101.             "" +
  102.             TTAG +
  103.             "" +
  104.             "</body>" +
  105.             "</html>"
  106.  
  107.         Const tableHead = "<h1>Products by Suppliers</h1>"
  108.  
  109.         Const tableFmt =
  110.             "<table id='products'>" +
  111.             "  <thead>" +
  112.             "    <th>Supplier</th>" +
  113.             "    <th>Description</th>" +
  114.             "    <th>Quantity Per Unit</th>" +
  115.             "    <th>Unit Price</th>" +
  116.             "  </thead>" +
  117.             "{0}" +
  118.             "</table>"
  119.  
  120.         Const dataRowFmt =
  121.             "  <tr>" +
  122.             "    <td>{0}</td>" +
  123.             "    <td>{1}</td>" +
  124.             "    <td>{2}</td>" +
  125.             "    <td align='right'>{3:C}</td>" +
  126.             "  </tr>"
  127.  
  128.         Dim ds = New DataSet()
  129.         ds.ReadXml(Path.Combine("Resources", "data", "GcNWind.xml"))
  130.  
  131.         Dim dtProds = ds.Tables("Products")
  132.         Dim dtSupps = ds.Tables("Suppliers")
  133.  
  134.         Dim products =
  135.             (From prod In dtProds.Select()
  136.              Join supp In dtSupps.Select()
  137.             On prod("SupplierID") Equals supp("SupplierID")
  138.              Order By supp("CompanyName")
  139.              Select New With
  140.                 {
  141.                     .ProductName = prod("ProductName"),
  142.                 .Supplier = supp("CompanyName"),
  143.                 .QuantityPerUnit = prod("QuantityPerUnit"),
  144.                 .UnitPrice = prod("UnitPrice")
  145.             }).Take(16)
  146.  
  147.         Dim sb = New StringBuilder()
  148.         sb.AppendLine(tableHead)
  149.         For Each prod In products
  150.             sb.AppendFormat(dataRowFmt, prod.Supplier, prod.ProductName, prod.QuantityPerUnit, prod.UnitPrice)
  151.         Next
  152.  
  153.         Dim html = tableTpl.Replace(TTAG, String.Format(tableFmt, sb.ToString()))
  154.  
  155.         Dim tfile = Path.GetTempFileName()
  156.         Dim ms = New MemoryStream()
  157.         '' We use GcHtmlBrowser to render the whole generated HTML to an image.
  158.         '' Note that GcHtmlBrowser natively supports only JPEG, PNG and WEBP formats.
  159.         '' In this sample we limit the output to those formats.
  160.         '' For a more flexible approach that allows rendering HTML into any
  161.         '' image format supported by DsImaging, please see HtmlRenderPage0.
  162.         Using browser = Util.NewHtmlBrowser(), htmlPage = browser.NewPage(html, New PageOptions() With {.WindowSize = pixelSize})
  163.             Select Case targetMime
  164.                 Case MimeTypes.JPEG
  165.                     htmlPage.SaveAsJpeg(tfile)
  166.                 Case MimeTypes.PNG
  167.                     htmlPage.SaveAsPng(tfile)
  168.                 Case MimeTypes.WEBP
  169.                     htmlPage.SaveAsWebp(tfile)
  170.                 Case Else
  171.                     Throw New Exception("Unsupported image format.")
  172.             End Select
  173.         End Using
  174.         '' Copy the created image from the temp file to target stream:
  175.         Using ts = File.OpenRead(tfile)
  176.             ts.CopyTo(ms)
  177.         End Using
  178.         '' Clean up:
  179.         File.Delete(tfile)
  180.         '' Done.
  181.         Return ms
  182.     End Function
  183. End Class
  184.