/// <summary>
/// Calculates the bitmap dimensions and creates a new bitmap (if requested) with text drawn to
/// according to the settings applied to this text renderer.
/// </summary>
/// <param name="isRequestingBitmapInfoOnly">
/// <para>Set to true to not produce a bitmap and measure what the bitmap size will be instead.</para>
/// <para>Set to false to create a bitmap with text rendered to it.</para>
/// </param>
/// <returns>
/// <para>
/// Returns a result object with the requested bitmap data if flagged successful.
/// If the "isRequestingBitmapInfoOnly" argument was set true, then the result object will only provide
/// BitmapInfo and its Bitmap property will be null.
/// </para>
/// <para>
/// Returns a failure result object if there was an error, in which case the the result's Message property
/// would provide details as to what went wrong.
/// </para>
/// </returns>
private TextBitmapDataResult AcquireBitmapData(bool isRequestingBitmapInfoOnly)
{
// Do not continue if there is no text to render.
if (fSettings.Text.Length <= 0)
{
return(new TextBitmapDataResult("No text to render."));
}
// Do not continue if not called on the main UI thread.
// Note: Microsoft's WriteableBitmap.render() method used below can only be called on the main UI thread.
if (System.Windows.Deployment.Current.Dispatcher.CheckAccess() == false)
{
return(new TextBitmapDataResult("Text can only be rendered on the main UI thread."));
}
// Do not continue if Corona is currently synchronized with the rendering thread.
// Note: Calling the WriteableBitmap.render() while the rendering thread is blocked will cause deadlock.
if (Direct3DSurfaceAdapter.IsSynchronizedWithRenderingThread)
{
return(new TextBitmapDataResult("Cannot render text while Corona is synchronized with the rendering thread."));
}
// Create a Xaml text control to be used to render text to a bitmap.
var textBlock = new System.Windows.Controls.TextBlock();
textBlock.Foreground = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Colors.White);
textBlock.VerticalAlignment = System.Windows.VerticalAlignment.Top;
textBlock.Text = fSettings.Text;
// Set up the font.
if (string.IsNullOrEmpty(fSettings.FontSettings.FamilyName) == false)
{
if (string.IsNullOrEmpty(fSettings.FontSettings.FilePath) == false)
{
System.IO.FileStream stream = null;
try
{
stream = System.IO.File.OpenRead(fSettings.FontSettings.FilePath);
textBlock.FontSource = new System.Windows.Documents.FontSource(stream);
}
catch (Exception) { }
finally
{
if (stream != null)
{
try
{
stream.Close();
stream.Dispose();
}
catch (Exception) { }
}
}
}
textBlock.FontFamily = new System.Windows.Media.FontFamily(fSettings.FontSettings.FamilyName);
}
textBlock.FontSize = fSettings.FontSettings.PointSize;
textBlock.FontWeight =
fSettings.FontSettings.IsBold ? System.Windows.FontWeights.Bold : System.Windows.FontWeights.Normal;
textBlock.FontStyle =
fSettings.FontSettings.IsItalic ? System.Windows.FontStyles.Italic : System.Windows.FontStyles.Normal;
// Set up the horizontal alignment of the text.
if (fSettings.HorizontalAlignment == WinRT.Interop.Graphics.HorizontalAlignment.Center)
{
textBlock.TextAlignment = System.Windows.TextAlignment.Center;
}
else if (fSettings.HorizontalAlignment == WinRT.Interop.Graphics.HorizontalAlignment.Right)
{
textBlock.TextAlignment = System.Windows.TextAlignment.Right;
}
else
{
textBlock.TextAlignment = System.Windows.TextAlignment.Left;
}
// Set up multiline text wrapping if enabled.
if (fSettings.BlockWidth > 0)
{
// Enable text wrapping at the given pixel width.
textBlock.TextWrapping = System.Windows.TextWrapping.Wrap;
textBlock.MaxWidth = (double)fSettings.BlockWidth;
textBlock.Width = (double)fSettings.BlockWidth;
}
else
{
// Disable text wrapping.
textBlock.TextWrapping = System.Windows.TextWrapping.NoWrap;
}
if (fSettings.BlockHeight > 0)
{
textBlock.MaxHeight = (double)fSettings.BlockHeight;
textBlock.Height = (double)fSettings.BlockHeight;
}
// Calculate a pixel width and height for the bitmap to render text to.
int bitmapWidth = fSettings.BlockWidth;
if (bitmapWidth <= 0)
{
bitmapWidth = (int)(Math.Ceiling(textBlock.ActualWidth) + 0.1);
}
if ((fSettings.ClipWidth > 0) && (bitmapWidth > fSettings.ClipWidth))
{
bitmapWidth = fSettings.ClipWidth;
}
int bitmapHeight = fSettings.BlockHeight;
if (bitmapHeight <= 0)
{
bitmapHeight = (int)(Math.Ceiling(textBlock.ActualHeight) + 0.1);
}
if ((fSettings.ClipHeight > 0) && (bitmapHeight > fSettings.ClipHeight))
{
bitmapHeight = fSettings.ClipHeight;
}
// Stop here if the caller is only requesting the resulting bitmap's measurements.
if (isRequestingBitmapInfoOnly)
{
var bitmapSettings = new WinRT.Interop.Graphics.BitmapSettings();
bitmapSettings.PixelFormat = WinRT.Interop.Graphics.PixelFormat.Grayscale;
bitmapSettings.PremultipliedAlphaApplied = true;
bitmapSettings.PixelWidth = bitmapWidth;
bitmapSettings.PixelHeight = bitmapHeight;
return(new TextBitmapDataResult(new WinRT.Interop.Graphics.BitmapInfo(bitmapSettings)));
}
// Determine if the text contains any visible/printable characters.
bool hasPrintableCharacters = false;
foreach (char nextCharacter in textBlock.Text.ToCharArray())
{
if ((System.Char.IsWhiteSpace(nextCharacter) == false) && (System.Char.IsControl(nextCharacter) == false))
{
hasPrintableCharacters = true;
break;
}
}
// If there is no text to render, then stop here and return an empty bitmap.
// Note: This is a huge optimization. No point in rendering text below if you can't see the characters.
if (hasPrintableCharacters == false)
{
var bitmapSettings = new WinRT.Interop.Graphics.BitmapSettings();
bitmapSettings.PixelFormat = WinRT.Interop.Graphics.PixelFormat.Grayscale;
bitmapSettings.PremultipliedAlphaApplied = true;
bitmapSettings.PixelWidth = bitmapWidth;
bitmapSettings.PixelHeight = bitmapHeight;
var emptyGrayscaleBitmap = new WinRT.Interop.Graphics.Bitmap();
emptyGrayscaleBitmap.FormatUsing(new WinRT.Interop.Graphics.BitmapInfo(bitmapSettings));
return(new TextBitmapDataResult(emptyGrayscaleBitmap));
}
// If the text has been clipped, then shift the text within the bounds of the bitmap.
System.Windows.Media.TranslateTransform transform = null;
if (textBlock.ActualWidth > (double)bitmapWidth)
{
transform = new System.Windows.Media.TranslateTransform();
if (textBlock.TextAlignment == System.Windows.TextAlignment.Right)
{
transform.X = bitmapWidth - textBlock.ActualWidth;
}
else if (textBlock.TextAlignment == System.Windows.TextAlignment.Center)
{
transform.X = (bitmapWidth - textBlock.ActualWidth) / 2.0;
}
}
// Render the text to a 32-bit color bitmap.
System.Windows.Media.Imaging.WriteableBitmap writeableBitmap = null;
try
{
// Create the bitmap.
writeableBitmap = new System.Windows.Media.Imaging.WriteableBitmap(bitmapWidth, bitmapHeight);
// Create a rectangle used to render a black background.
var backgroundColor = System.Windows.Media.Colors.Black;
var backgroundRectangle = new System.Windows.Shapes.Rectangle();
backgroundRectangle.Width = bitmapWidth;
backgroundRectangle.Height = bitmapHeight;
backgroundRectangle.Fill = new System.Windows.Media.SolidColorBrush(backgroundColor);
// Convert the background color object to a 32-bit integer.
// To be compared with the bitmap's integer pixel array below.
int backgroundColorAsInt32 =
((int)backgroundColor.B) |
((int)backgroundColor.G << 8) |
((int)backgroundColor.R << 16) |
((int)backgroundColor.A << 24);
// Attempt to render text to the bitmap.
// Note: There is a bug on Windows Phone where WriteableBitmap sometimes fails to render/inavlidate
// content if a Xaml DrawingSurfaceBackgroundGrid is being used by the application.
// If this happens, then we must attempt to render again. There is no other known work-around.
bool wasDrawn = false;
for (int renderAttempt = 1; renderAttempt <= 3; renderAttempt++)
{
// Notify the owner(s) that we're about to render to the bitmap.
if (this.Rendering != null)
{
this.Rendering.Invoke(this, new DotNetWriteableBitmapEventArgs(writeableBitmap));
}
// Render the text and its black background to the bitmap.
writeableBitmap.Render(backgroundRectangle, null);
writeableBitmap.Render(textBlock, transform);
writeableBitmap.Invalidate();
// --- Verify that the above text was successfully drawn to the bitmap. ---
// First, check that the black rectangle was drawn to the bitmap.
// This is a fast check because we only need to read one pixel in the bitmap's top-left corner.
if (writeableBitmap.Pixels[0] != backgroundColorAsInt32)
{
continue;
}
// Next, check that text was drawn to the bitmap.
if (hasPrintableCharacters)
{
// Traverse all pixels in the bitmap until we find 1 pixel that does not match the background color.
for (int pixelIndex = writeableBitmap.Pixels.Length - 1; pixelIndex >= 0; pixelIndex--)
{
if (writeableBitmap.Pixels[pixelIndex] != backgroundColorAsInt32)
{
wasDrawn = true;
break;
}
}
}
else
{
// The given text does not contain any visible characters. So, we're done.
wasDrawn = true;
}
// Stop now if we've successfully drawn to the bitmap.
if (wasDrawn)
{
break;
}
}
// Log a failure if we were unable to render text.
// Note: This still returns a bitmap. Should we?
if (wasDrawn == false)
{
String message = "Failed to create a bitmap for text: \"" + textBlock.Text + "\"\r\n";
Corona.WinRT.Interop.Logging.LoggingServices.Log(message);
}
}
catch (Exception ex)
{
return(new TextBitmapDataResult(ex.Message));
}
// Convert the 32-bit color bitmap to 8-bit grayscale.
var rgbaBitmap = DotNetBitmap.From(writeableBitmap);
var bitmapConveter = new WinRT.Interop.Graphics.BitmapConverter();
bitmapConveter.PixelFormat = WinRT.Interop.Graphics.PixelFormat.Grayscale;
var grayscaleBitmap = bitmapConveter.CreateBitmapFrom(rgbaBitmap);
rgbaBitmap.ReleaseByteBuffer();
if (grayscaleBitmap == null)
{
return(new TextBitmapDataResult("Failed to convert the 32-bit color text to a grayscale bitmap."));
}
// Return the text as a grayscaled bitmap.
return(new TextBitmapDataResult(grayscaleBitmap));
}
/// <summary>Decodes the given image file and returns an uncompressed bitmap.</summary>
/// <param name="filePath">The name and path of the image file to be decoded.</param>
/// <returns>
/// <para>Returns the result of the image decoding operation.</para>
/// <para>
/// If the result object's HasSucceeded property is set true, then this decoder succeeded in decoding
/// the given image file and the result object's Bitmap property would provide the bitmap that was produced.
/// </para>
/// <para>
/// If the result object's HasSucceeded property is false, then this decoder failed to decode the
/// given image file. The reason why would then be provided by the result object's Message property.
/// </para>
/// </returns>
public WinRT.Interop.Graphics.BitmapResult DecodeFromFile(string filePath)
{
// Validate the given image file path.
if (String.IsNullOrEmpty(filePath))
{
return(WinRT.Interop.Graphics.BitmapResult.FailedWith("Image decoder given a null or empty string."));
}
// Check that the given file exists and if its an external or embedded resource file.
bool isExternalFile = true;
var resourceServices = Corona.WinRT.Interop.Storage.DotNetResourceServices.Instance;
if (System.IO.File.Exists(filePath) == false)
{
if (resourceServices.ContainsFile(filePath) == false)
{
String message = String.Format("Image file '{0}' not found.", filePath);
return(WinRT.Interop.Graphics.BitmapResult.FailedWith(message));
}
isExternalFile = false;
}
// Ensure that the preferred pixel format is in the supported pixel format set.
fSettings.SupportedPixelFormats.Add(fSettings.PreferredPixelFormat);
Corona.WinRT.Interop.Graphics.IBitmap bitmap = null;
System.IO.Stream stream = null;
try
{
if (isExternalFile)
{
stream = System.IO.File.OpenRead(filePath);
}
else
{
stream = resourceServices.OpenFile(filePath);
}
var writeableBitmap = new System.Windows.Media.Imaging.WriteableBitmap(0, 0);
writeableBitmap.SetSource(stream);
bitmap = DotNetBitmap.From(writeableBitmap);
writeableBitmap = null;
// Convert the loaded bitmap if it does not meet the decoder's requirements.
if ((fSettings.SupportedPixelFormats.Contains(bitmap.Info.PixelFormat) == false) ||
(bitmap.Info.PixelWidth > fSettings.MaxPixelWidth) ||
(bitmap.Info.PixelHeight > fSettings.MaxPixelHeight))
{
var converter = new WinRT.Interop.Graphics.BitmapConverter();
converter.CopySettingsFrom(this);
// if (converter.CanConvert(bitmap))
// {
// converter.Convert(bitmap);
// }
// else
// {
var convertedBitmap = converter.CreateBitmapFrom(bitmap);
bitmap.ReleaseByteBuffer();
bitmap = convertedBitmap;
// }
}
}
catch (Exception ex)
{
if (bitmap != null)
{
try { bitmap.ReleaseByteBuffer(); }
catch (Exception) { }
}
return(WinRT.Interop.Graphics.BitmapResult.FailedWith(ex.Message));
}
finally
{
if (stream != null)
{
try
{
stream.Close();
stream.Dispose();
}
catch (Exception) { }
}
}
if (bitmap == null)
{
return(WinRT.Interop.Graphics.BitmapResult.FailedWith("Failed to load bitmap"));
}
return(WinRT.Interop.Graphics.BitmapResult.SucceededWith(bitmap));
}
