fbs/fontandbitmapserver/sfbs/fbsglyphdataiterator.cpp
branchRCL_3
changeset 163 bbf46f59e123
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fbs/fontandbitmapserver/sfbs/fbsglyphdataiterator.cpp	Tue Aug 31 16:31:06 2010 +0300
@@ -0,0 +1,465 @@
+// Copyright (c) 2009-2010 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of "Eclipse Public License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.eclipse.org/legal/epl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+//
+
+#include <e32def.h>
+#include <gdi.h>
+#include <graphics/gdi/gdistructs.h>
+#include <graphics/gdi/gdiconsts.h>
+#include <graphics/fbsglyphdataiterator.h>
+#include "FbsMessage.h"
+#include "UTILS.H"
+
+const TInt KFbsGlyphDataIterCodeInvalid = -1;
+
+extern void Panic(TFbsPanic aPanic);
+
+/**
+The default constructor sets the iterator to a closed and empty state. It 
+is the only way of constructing an iterator as instances cannot be copied by 
+assignment or passed by value.
+ */
+EXPORT_C RFbsGlyphDataIterator::RFbsGlyphDataIterator() :
+    iImpl(NULL)
+    {
+    }
+
+/**
+For a given font (aFont), this method retrieves the glyph data for a list of 
+glyph codes (aGlyphCodes), containing a number (aCount) of codes. On success, 
+the iterator is initialised with the data for the first glyph in aGlyphCodes.
+
+The memory allocated to aGlyphCodes must not be freed or altered while the 
+iterator is in use (i.e. until the iterator has been closed). 
+
+Open() may not be called on an already open iterator. In order to re-open an 
+iterator, it must first be closed by a call tor Close().
+
+If a glyph code is passed in that is not a recognised glyph code for the 
+associated font, an empty-box glyph will be returned. This behaviour is 
+consistent with CFbsFont::GetCharacterData().
+
+@pre The iterator is not already open. 
+
+@param aFont The font to provide the glyph code data for.
+@param aGlyphCodes An array of glyph codes that the iterator will 
+	provide data for. This memory allocated for this array must not be 
+	freed before the iterator is closed.
+@param aCount The number of glyph codes in aGlyphCodes.
+
+@return 
+	KErrNone, if the iterator is successfully initialised to retrieve 
+		the glyph data;
+	KErrInUse, if the iterator is already open, in which case the state of
+        the iterator is left unchanged;
+	KErrNoMemory, if the iterator cannot be opened due to insufficient 
+		system memory;
+	KErrNotSupported, if aFont refers to a bitmap font or an outline & shadow
+        font, if the required version of the hardware driver is not available
+        (EGL 1.3 or later is required), or if RSgImages are not supported by
+        the system;
+	KErrArgument, if aCount is negative or zero, or if aGlyphCodes is null.
+ */
+EXPORT_C TInt RFbsGlyphDataIterator::Open(CFbsFont& aFont, const TUint* aGlyphCodes, TInt aCount)
+	{  
+	if (iImpl)
+		{
+		return KErrInUse;
+		}
+	if ((aCount <= 0) || !aGlyphCodes)
+		{
+		return KErrArgument;
+		}
+	if (!aFont.Address()->IsOpenFont())
+        {
+        return KErrNotSupported;
+        }
+    TInt glyphBitmapType = aFont.Address()->GlyphBitmapType();
+    if (!( (glyphBitmapType == EMonochromeGlyphBitmap) || (glyphBitmapType == EAntiAliasedGlyphBitmap) ))
+        {
+        //Only supported bitmap types can be used i.e. EMonochromeGlyphBitmap or EAntiAliasedGlyphBitmap
+        return KErrNotSupported;
+        }
+    // Check that the max width and height of the font are both no more than 2048.
+    // This is the smallest maximum size an RSgImage can be created with.
+    // This limit is arbitrarily set as it should cover nearly all use cases.
+    const TInt KMaxFontSizeInPixels = 2048;
+    TInt maxHeight = aFont.FontMaxHeight();
+    TInt maxWidth = aFont.MaxCharWidthInPixels();
+    if ( (KMaxFontSizeInPixels < maxHeight) || (KMaxFontSizeInPixels < maxWidth) )
+        {
+        return KErrTooBig;
+        }
+    // Construct implementor object that holds the state for the iterator.
+	iImpl = new CGlyphDataIteratorImpl(aFont.iHandle, aGlyphCodes, aCount);
+	if (!iImpl)
+	    {
+	    return KErrNoMemory;
+	    }
+	TInt err = iImpl->Initialise();
+	if (err != KErrNone)
+	    {
+        Close();
+	    }
+	return err;   
+	}
+
+/**
+Moves the iterator to the data for the next glyph code in the array passed 
+into RFbsGlyphDataIterator::Open(). Data for the glyph can then be accessed 
+using the Image(), Rect() and Metrics() methods.
+
+Once Next() has been called, the references returned by Image(), Rect() and 
+Metrics() methods during the previous iteration should be considered invalid 
+and must be discarded. 
+
+Calling Next() repeatedly will iterate through the glyph data for all the glyph
+codes, until it has reached the last glyph code in the array (assuming no errors
+are encountered), at which point KErrNotFound is returned, and the array of glyph
+codes passed to RFbsGlyphDataIterator::Open() can safely be deleted.
+
+If the call was successful, KErrNone is returned. If an error is encountered an
+error code will be returned and the state of the iterator is left unchanged.
+
+@pre The iterator has been opened by a successful call to Open().
+@post The properties of the iterator are of the glyph corresponding
+	to the next code passed in the array to Open().	However, if an error code 
+	was returned, the state of the iterator	is unchanged.
+	
+@return 
+	KErrNone, if the iterator was successfully advanced;
+	KErrNotFound, if the iterator is already at the last element and cannot
+		be advanced any further;
+	KErrNoMemory, if there is insufficient system memory available;
+	KErrNoGraphicsMemory, if there is insufficient graphics memory available.
+	
+@panic FBSCLI 31, if the iterator is not open.
+@panic FBSERV -8, if as a result of this call, communication with the 
+    server is invoked, and the associated CFbsFont has been destroyed.
+ */
+EXPORT_C TInt RFbsGlyphDataIterator::Next()
+    {
+    __ASSERT_ALWAYS(iImpl, Panic(EFbsPanicGlyphDataIteratorClosed));
+    return iImpl->Next();
+    }
+
+/**
+Closes the iterator and releases its internal resources. After calling, all data 
+retrieved by the iterator is no longer safe to use. Once closed, this iterator 
+can be re-opened. Calling Close() on an already closed iterator has no effect.
+
+Once an iterator is closed, the array of glyphs (aGlyphCodes) passed to
+RFbsGlyphDataIterator::Open() can safely be deleted.
+
+@post The iterator is closed.
+ */
+EXPORT_C void RFbsGlyphDataIterator::Close()
+    {
+    delete iImpl;
+    iImpl = NULL;
+    }
+
+/**
+Returns a reference to the RSgImage that contains the glyph for the current 
+iteration. The image representation of the glyph is the same as the image 
+returned by the existing CFbsFont::GetCharacterData() method (i.e. an alpha mask). 
+
+The RSgImage should only be considered a temporary handle for use in this 
+iteration, and should not be used after a call to Next() or Close() has 
+been made.
+
+Note: For glyphs such as space which have no visible representation, Image() 
+will return a null image handle (i.e. RSgImage::IsNull() returns ETrue). This 
+cannot be used for drawing. In this case Rect() will be empty however 
+Metrics() will still be valid. 
+
+@pre The iterator has been initialised by successfully calling Open().
+     
+@return A handle to the image where the glyph for this iteration is stored.
+     
+@panic FBSCLI 31, if the iterator is not open.
+ */
+EXPORT_C const RSgImage& RFbsGlyphDataIterator::Image() const
+    {
+    __ASSERT_ALWAYS(iImpl, Panic(EFbsPanicGlyphDataIteratorClosed));
+    __ASSERT_DEBUG(!iImpl->iGlyphBatch.IsEmpty(), Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    return iImpl->iGlyphBatch.First()->iImage;
+    }
+
+/**
+Returns the area within the RSgImage where the glyph for the current
+iteration is located. The reference returned by Rect() should be considered 
+temporary for use within this iteration and should not be used after a call to 
+Next() or Close() has been made.
+ 
+@pre The iterator has been initialised by successfully calling Open().
+     
+@return A rectangle representing the position and size in pixels, 
+	of the glyph for this iteration on the RSgImage provided by Image().
+     
+@panic FBSCLI 31, if the iterator is not open.
+ */
+EXPORT_C const TRect& RFbsGlyphDataIterator::Rect() const
+    {
+    __ASSERT_ALWAYS(iImpl, Panic(EFbsPanicGlyphDataIteratorClosed));
+    __ASSERT_DEBUG(!iImpl->iGlyphBatch.IsEmpty(), Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    return iImpl->iGlyphDataIterRect;
+    }
+
+/**
+Returns the glyph metrics for the current iteration. The reference returned by 
+Metrics() should be considered temporary for use within this iteration and 
+should not be used after a call to Next() or Close() has been made.
+
+@pre The iterator has been initialised by successfully calling Open().
+ 
+@return The metrics for the glyph at the current iteration.
+
+@panic FBSCLI 31, if the iterator is not open.
+ */
+EXPORT_C const TOpenFontCharMetrics& RFbsGlyphDataIterator::Metrics() const
+    {
+    __ASSERT_ALWAYS(iImpl, Panic(EFbsPanicGlyphDataIteratorClosed));
+    __ASSERT_DEBUG(!iImpl->iGlyphBatch.IsEmpty(), Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    return iImpl->iGlyphBatch.First()->iInfo.iMetrics;
+    }
+
+/**
+Returns the glyph code associated with the data for the current iteration.
+
+@pre The iterator has been initialised by successfully calling Open().
+ 
+@return The glyph code of the glyph at the current iteration.
+
+@panic FBSCLI 31, if the iterator is not open.
+ */
+EXPORT_C TUint RFbsGlyphDataIterator::GlyphCode() const
+    {
+    __ASSERT_ALWAYS(iImpl, Panic(EFbsPanicGlyphDataIteratorClosed));
+    __ASSERT_DEBUG(!iImpl->iGlyphBatch.IsEmpty(), Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    return iImpl->iGlyphDataIterCodes[iImpl->iGlyphDataIterCodeIndex];
+    }
+
+
+/**
+Constructs a CGlyphDataIteratorImpl. 
+@param aFbsFontHandle The handle of the FbsFont that the iterator is working with.
+@param aGlyphCodes The array of glyph codes sent to RFbsGlyphDataIterator::Open()
+@param aCount The number of glyph codes in aGlyphCodes.
+ */
+CGlyphDataIteratorImpl::CGlyphDataIteratorImpl(TInt aFbsFontHandle, const TUint* aGlyphCodes, TInt aCount) :
+    iGlyphBatch(_FOFF(TGlyphBatchItem, iLink)),
+    iGlyphDataIterCodes(aGlyphCodes),
+    iGlyphDataIterCodeCount(aCount),
+    iGlyphDataIterCodeIndex(KFbsGlyphDataIterCodeInvalid),
+    iFbsFontHandle(aFbsFontHandle)
+    {
+    }
+
+/** 
+Destructor. Releases all resources, disconnects from server and frees any
+items in the list of batched items.
+ */
+CGlyphDataIteratorImpl::~CGlyphDataIteratorImpl()
+    {
+    if (iFbs)
+        {
+        if (iGlyphDataIterCodeIndex != KFbsGlyphDataIterCodeInvalid)
+            {
+            //Send the No-Op command to ensure that the "In Transit" RSgImage(s) are closed.
+            iFbs->SendCommand(EFbsMessNoOp);
+            }
+        RFbsSession::Disconnect();
+        iFbs = NULL;
+        }
+    while (!iGlyphBatch.IsEmpty())
+        {
+        TGlyphBatchItem* item = iGlyphBatch.First();
+        item->iImage.Close();
+        iGlyphBatch.Remove(*item);
+        delete item;
+        }
+    iGlyphBatch.Reset();
+    }
+
+/**
+Sets up the CGlyphDataIteratorImpl, populating the first batch of glyphs.
+Should only be called once, immediately after construction.
+ */
+TInt CGlyphDataIteratorImpl::Initialise()
+    {
+    __ASSERT_DEBUG(iFbsFontHandle, Panic(EFbsPanicGlyphDataIteratorInvalidState));    
+    __ASSERT_DEBUG(iGlyphDataIterCodes, Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    __ASSERT_DEBUG(iGlyphDataIterCodeCount, Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    __ASSERT_DEBUG(iGlyphDataIterCodeIndex == KFbsGlyphDataIterCodeInvalid, Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    
+    // If the client already has a session open, this is just a reference counting exercise and should incur no performance impact.
+    TInt err = RFbsSession::Connect();
+    if (err == KErrNone)
+        {
+        iFbs = RFbsSession::GetSession();
+        err = UpdateGlyphBatch(0);
+        }
+    if (err == KErrNone)
+        {
+        iGlyphDataIterCodeIndex = 0;
+        UpdateGlyphRect();
+        }
+    return err;
+    }
+
+/**
+Increments the current iteration if possible, re-sending the request
+for more glyphs if the current batch of glyphs is down to the last
+item.
+@see RFbsGlyphDataIterator::Next()
+ */
+TInt CGlyphDataIteratorImpl::Next()
+    {
+    __ASSERT_DEBUG(!iGlyphBatch.IsEmpty(), Panic(EFbsPanicGlyphDataIteratorInvalidState));
+    if ( (iGlyphDataIterCodeIndex + 1) >= iGlyphDataIterCodeCount) 
+        {
+        return KErrNotFound; 
+        }
+    TInt err = UpdateGlyphBatch(iGlyphDataIterCodeIndex + 1);
+    if (err == KErrNone)
+        {
+        ++iGlyphDataIterCodeIndex;
+        // Close the current image and pop the head of the batch.
+        TGlyphBatchItem* item = iGlyphBatch.First();
+        item->iImage.Close();
+        iGlyphBatch.Remove(*item);
+        delete item;
+        __ASSERT_DEBUG(!iGlyphBatch.IsEmpty(), Panic(EFbsPanicGlyphDataIteratorInvalidState));
+        UpdateGlyphRect();
+        }
+    return err;
+    }
+
+/**
+Checks whether a call to the server is required to get a new batch of glyph 
+info, and processes the response from the server as necessary.
+
+@param aIndex Specifies the index into the glyph array which needs to be in
+the active glyph batch. If it is not there, a request is made to the server
+to get it.
+@return KErrNone if getting at least one glyph succeeded or a call to the
+    server was not necessary, otherwise one of the system wide error codes.
+@panic FBSCLI 31 (debug only), if the iterator is not open
+@panic FBSCLI 33 (debug only), if an unexpected number of glyphs was received
+    as a result of requesting glyphs from the server, or if the current batch
+    of glyphs is empty when there should be at least one item.
+ */
+TInt CGlyphDataIteratorImpl::UpdateGlyphBatch(TInt aIndex)
+    {
+    __ASSERT_DEBUG(Rng(0, aIndex, iGlyphDataIterCodeCount - 1), Panic(EFbsPanicGlyphDataIteratorIndexOutOfRange));
+
+    TInt err = KErrNone;
+    
+    TBool needMoreGlyphs = EFalse;
+    if (iGlyphBatch.IsEmpty())
+        {
+        // Current batch is empty, must request more. Should only get here when the iterator 
+        // is first opened, since one item should always be in the list from then on.
+        __ASSERT_DEBUG(aIndex == 0, Panic(EFbsPanicGlyphDataIteratorInvalidState));
+        needMoreGlyphs = ETrue;
+        }
+    else if (iGlyphBatch.IsLast(iGlyphBatch.First()))
+        {
+        // Only one item in the list. 
+        needMoreGlyphs = ETrue;
+        }
+    
+    if (needMoreGlyphs)
+        {
+        // If the array of batched images is empty OR only one left, means we need to request a new batch.
+        // We make sure there is at least one glyph in the batch so the iterator is always usable even
+        // when a failure to move to the next iteration occurs.
+    
+        TBool glyphAddedToBatch = EFalse;
+        TUint glyphCodes[KMaxGlyphBatchSize];
+        
+        TInt numGlyphsToRequest = Min(iGlyphDataIterCodeCount - aIndex, KMaxGlyphBatchSize);        
+        (void)Mem::Copy(glyphCodes, &(iGlyphDataIterCodes[aIndex]), sizeof(TUint) * numGlyphsToRequest);
+        TPckg<TUint[KMaxGlyphBatchSize]> argGlyphCodes(glyphCodes);
+        
+        TGlyphImageInfo rcvdGlyphInfo[KMaxGlyphBatchSize];
+        TPckg<TGlyphImageInfo[KMaxGlyphBatchSize]> argGlyphInfo(rcvdGlyphInfo);
+        
+        if (numGlyphsToRequest < KMaxGlyphBatchSize)
+            {
+            argGlyphCodes.SetLength(numGlyphsToRequest * sizeof(TUint));
+            argGlyphInfo.SetLength(numGlyphsToRequest * sizeof(TGlyphImageInfo));
+            }
+        
+        err = iFbs->SendCommand(EFbsMessGetGlyphs, TIpcArgs(iFbsFontHandle, &argGlyphCodes, &argGlyphInfo));
+        if (err == KErrNone)
+            {
+            __ASSERT_DEBUG(argGlyphInfo.Length() % sizeof(TGlyphImageInfo) == 0, Panic(EFbsPanicGlyphDataIteratorInvalidState));
+            TInt numRcvdGlyphs = argGlyphInfo.Length() / sizeof(TGlyphImageInfo);
+            __ASSERT_DEBUG(numRcvdGlyphs > 0, Panic(EFbsPanicGlyphDataIteratorInvalidState));
+            __ASSERT_DEBUG(numRcvdGlyphs <= KMaxGlyphBatchSize, Panic(EFbsPanicGlyphDataIteratorInvalidState));
+            
+            // Store the received glyph data, and open the image handles so that the IDs
+            // will not be released by FbServ between now and the client using them.
+            // If a failure occurs while processing one of the recevied glyphs,
+            // abort the rest but keep the ones that succeeded.
+            for (TInt i = 0; (i < numRcvdGlyphs) && (err == KErrNone); ++i)
+                {
+                TGlyphBatchItem* glyphEntry = new TGlyphBatchItem;
+                if (!glyphEntry)
+                    {
+                    err = KErrNoMemory;
+                    }
+                else
+                    {
+                    glyphEntry->iInfo = rcvdGlyphInfo[i];
+                    
+                    RSgImage glyphImage;
+                    if (rcvdGlyphInfo[i].iImageId != KSgNullDrawableId)
+                        {
+                        err = glyphEntry->iImage.Open(rcvdGlyphInfo[i].iImageId);
+                        }
+                    if (err == KErrNone)
+                        {
+                        iGlyphBatch.AddLast(*glyphEntry);
+                        glyphAddedToBatch = ETrue;
+                        }
+                    else
+                        {
+                        delete glyphEntry;
+                        }
+                    }
+                }
+            }
+        if (err != KErrNone && glyphAddedToBatch)
+            {
+            // There was an error adding an item to the batch. Rather than return the
+            // error to the client, ignore it and use what glyphs we successfully batched.
+            err = KErrNone; 
+            }
+        }    
+    return err;
+    }
+
+/**
+Updates the glyph rectangle member based on the current glyph metrics.
+@post The iGlyphDataIterRect member is updated to reflect the position
+    and size of the currently active glyph.
+ */
+void CGlyphDataIteratorImpl::UpdateGlyphRect()
+    {
+    iGlyphDataIterRect.iTl = TPoint(iGlyphBatch.First()->iInfo.iPosX, iGlyphBatch.First()->iInfo.iPosY);
+    iGlyphDataIterRect.SetSize(TSize(iGlyphBatch.First()->iInfo.iMetrics.Width(), iGlyphBatch.First()->iInfo.iMetrics.Height()));
+    }