path: root/indra/newview/llpreviewtexture.cpp

/**
 * @file llpreviewtexture.cpp
 * @brief LLPreviewTexture class implementation
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"

#include "llwindow.h"

#include "llpreviewtexture.h"

#include "llagent.h"
#include "llbutton.h"
#include "llcombobox.h"
#include "llfilepicker.h"
#include "llfloaterreg.h"
#include "llimagetga.h"
#include "llimagepng.h"
#include "llinventory.h"
#include "llinventorymodel.h"
#include "llnotificationsutil.h"
#include "llresmgr.h"
#include "lltrans.h"
#include "lltextbox.h"
#include "lltextureview.h"
#include "llui.h"
#include "llviewerinventory.h"
#include "llviewermenufile.h" // LLFilePickerReplyThread
#include "llviewertexture.h"
#include "llviewertexturelist.h"
#include "lluictrlfactory.h"
#include "llviewercontrol.h"
#include "llviewerwindow.h"
#include "lllineeditor.h"

#include <boost/lexical_cast.hpp>

const S32 CLIENT_RECT_VPAD = 4;

const F32 SECONDS_TO_SHOW_FILE_SAVED_MSG = 8.f;

const F32 PREVIEW_TEXTURE_MAX_ASPECT = 200.f;
const F32 PREVIEW_TEXTURE_MIN_ASPECT = 0.005f;


LLPreviewTexture::LLPreviewTexture(const LLSD& key)
    : LLPreview(key),
      mLoadingFullImage( false ),
      mSavingMultiple(false),
      mShowKeepDiscard(false),
      mCopyToInv(false),
      mIsCopyable(false),
      mIsFullPerm(false),
      mUpdateDimensions(true),
      mLastHeight(0),
      mLastWidth(0),
      mAspectRatio(0.f),
      mPreviewToSave(false),
      mImage(NULL),
      mImageOldBoostLevel(LLGLTexture::BOOST_NONE)
{
    updateImageID();
    if (key.has("save_as"))
    {
        mPreviewToSave = true;
    }
}

LLPreviewTexture::~LLPreviewTexture()
{
    LLLoadedCallbackEntry::cleanUpCallbackList(&mCallbackTextureList) ;

    if( mLoadingFullImage )
    {
        getWindow()->decBusyCount();
    }

    if (mImage.notNull())
    {
        mImage->setBoostLevel(mImageOldBoostLevel);
        mImage = NULL;
    }
}

void LLPreviewTexture::populateRatioList()
{
    // Fill in ratios list with common aspect ratio values
    mRatiosList.clear();
    mRatiosList.push_back(LLTrans::getString("Unconstrained"));
    mRatiosList.push_back("1:1");
    mRatiosList.push_back("4:3");
    mRatiosList.push_back("10:7");
    mRatiosList.push_back("3:2");
    mRatiosList.push_back("16:10");
    mRatiosList.push_back("16:9");
    mRatiosList.push_back("2:1");

    // Now fill combo box with provided list
    LLComboBox* combo = getChild<LLComboBox>("combo_aspect_ratio");
    combo->removeall();

    for (std::vector<std::string>::const_iterator it = mRatiosList.begin(); it != mRatiosList.end(); ++it)
    {
        combo->add(*it);
    }
}

// virtual
bool LLPreviewTexture::postBuild()
{
    mButtonsPanel = getChild<LLLayoutPanel>("buttons_panel");
    mDimensionsText = getChild<LLUICtrl>("dimensions");
    mAspectRatioText = getChild<LLUICtrl>("aspect_ratio");

    if (mCopyToInv)
    {
        getChild<LLButton>("Keep")->setLabel(getString("Copy"));
        childSetAction("Keep",LLPreview::onBtnCopyToInv,this);
        getChildView("Discard")->setVisible( false);
    }
    else if (mShowKeepDiscard)
    {
        childSetAction("Keep",onKeepBtn,this);
        childSetAction("Discard",onDiscardBtn,this);
    }
    else
    {
        getChildView("Keep")->setVisible( false);
        getChildView("Discard")->setVisible( false);
    }

    childSetAction("save_tex_btn", LLPreviewTexture::onSaveAsBtn, this);
    getChildView("save_tex_btn")->setVisible( true);
    getChildView("save_tex_btn")->setEnabled(canSaveAs());

    const LLInventoryItem* item = getItem();
    if (item)
    {
        if (!mCopyToInv)
        {
            childSetCommitCallback("desc", LLPreview::onText, this);
            getChild<LLUICtrl>("desc")->setValue(item->getDescription());
            getChild<LLLineEditor>("desc")->setPrevalidate(&LLTextValidate::validateASCIIPrintableNoPipe);
        }
        bool source_library = mObjectUUID.isNull() && gInventory.isObjectDescendentOf(item->getUUID(), gInventory.getLibraryRootFolderID());
        if (source_library)
        {
            getChildView("Discard")->setEnabled(false);
        }
    }

    // Fill in ratios list and combo box with common aspect ratio values
    populateRatioList();

    childSetCommitCallback("combo_aspect_ratio", onAspectRatioCommit, this);

    LLComboBox* combo = getChild<LLComboBox>("combo_aspect_ratio");
    combo->setCurrentByIndex(0);

    return LLPreview::postBuild();
}

// static
void LLPreviewTexture::onSaveAsBtn(void* data)
{
    LLPreviewTexture* self = (LLPreviewTexture*)data;
    self->saveAs();
}

void LLPreviewTexture::draw()
{
    updateDimensions();

    LLPreview::draw();

    if (!isMinimized())
    {
        LLGLSUIDefault gls_ui;
        gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);

        const LLRect& border = mClientRect;
        LLRect interior = mClientRect;
        interior.stretch( -PREVIEW_BORDER_WIDTH );

        // ...border
        gl_rect_2d( border, LLColor4(0.f, 0.f, 0.f, 1.f));
        gl_rect_2d_checkerboard( interior );

        if ( mImage.notNull() )
        {
            // Draw the texture
            gGL.diffuseColor3f( 1.f, 1.f, 1.f );
            gl_draw_scaled_image(interior.mLeft,
                                interior.mBottom,
                                interior.getWidth(),
                                interior.getHeight(),
                                mImage);

            // Pump the texture priority
            F32 pixel_area = mLoadingFullImage ? (F32)MAX_IMAGE_AREA  : (F32)(interior.getWidth() * interior.getHeight() );
            mImage->addTextureStats( pixel_area );

            // Don't bother decoding more than we can display, unless
            // we're loading the full image.
            if (!mLoadingFullImage)
            {
                S32 int_width = interior.getWidth();
                S32 int_height = interior.getHeight();
                mImage->setKnownDrawSize(int_width, int_height);
            }
            else
            {
                // Don't use this feature
                mImage->setKnownDrawSize(0, 0);
            }

            if( mLoadingFullImage )
            {
                LLFontGL::getFontSansSerif()->renderUTF8(LLTrans::getString("Receiving"), 0,
                    interior.mLeft + 4,
                    interior.mBottom + 4,
                    LLColor4::white, LLFontGL::LEFT, LLFontGL::BOTTOM,
                    LLFontGL::NORMAL,
                    LLFontGL::DROP_SHADOW);

                F32 data_progress = mImage->getDownloadProgress() ;

                // Draw the progress bar.
                const S32 BAR_HEIGHT = 12;
                const S32 BAR_LEFT_PAD = 80;
                S32 left = interior.mLeft + 4 + BAR_LEFT_PAD;
                S32 bar_width = getRect().getWidth() - left - RESIZE_HANDLE_WIDTH - 2;
                S32 top = interior.mBottom + 4 + BAR_HEIGHT;
                S32 right = left + bar_width;
                S32 bottom = top - BAR_HEIGHT;

                LLColor4 background_color(0.f, 0.f, 0.f, 0.75f);
                LLColor4 decoded_color(0.f, 1.f, 0.f, 1.0f);
                LLColor4 downloaded_color(0.f, 0.5f, 0.f, 1.0f);

                gl_rect_2d(left, top, right, bottom, background_color);

                if (data_progress > 0.0f)
                {
                    // Downloaded bytes
                    right = left + llfloor(data_progress * (F32)bar_width);
                    if (right > left)
                    {
                        gl_rect_2d(left, top, right, bottom, downloaded_color);
                    }
                }
            }
            else
            if( !mSavedFileTimer.hasExpired() )
            {
                LLFontGL::getFontSansSerif()->renderUTF8(LLTrans::getString("FileSaved"), 0,
                    interior.mLeft + 4,
                    interior.mBottom + 4,
                    LLColor4::white, LLFontGL::LEFT, LLFontGL::BOTTOM,
                    LLFontGL::NORMAL,
                    LLFontGL::DROP_SHADOW);
            }
        }
    }

}


// virtual
bool LLPreviewTexture::canSaveAs() const
{
    return mIsFullPerm && !mLoadingFullImage && mImage.notNull() && !mImage->isMissingAsset();
}


// virtual
void LLPreviewTexture::saveAs()
{
    if( mLoadingFullImage )
        return;

    std::string filename = getItem() ? LLDir::getScrubbedFileName(getItem()->getName()) : LLStringUtil::null;
    LLFilePickerReplyThread::startPicker(boost::bind(&LLPreviewTexture::saveTextureToFile, this, _1), LLFilePicker::FFSAVE_TGAPNG, filename);
}

void LLPreviewTexture::saveTextureToFile(const std::vector<std::string>& filenames)
{
    const LLInventoryItem* item = getItem();
    if (item && mPreviewToSave)
    {
        mPreviewToSave = false;
        LLFloaterReg::showTypedInstance<LLPreviewTexture>("preview_texture", item->getUUID());
    }

    // remember the user-approved/edited file name.
    mSaveFileName = filenames[0];
    mSavingMultiple = false;
    mLoadingFullImage = true;
    getWindow()->incBusyCount();

    LL_DEBUGS("FileSaveAs") << "Scheduling saving file to " << mSaveFileName << LL_ENDL;

    mImage->forceToSaveRawImage(0);//re-fetch the raw image if the old one is removed.
    mImage->setLoadedCallback(LLPreviewTexture::onFileLoadedForSave,
        0, true, false, new LLUUID(mItemUUID), &mCallbackTextureList);
}


void LLPreviewTexture::saveMultipleToFile(const std::string& file_name)
{
    std::string texture_location(gSavedSettings.getString("TextureSaveLocation"));
    std::string texture_name = LLDir::getScrubbedFileName(file_name.empty() ? getItem()->getName() : file_name);

    mSaveFileName = texture_location + gDirUtilp->getDirDelimiter() + texture_name + ".png";

    mSavingMultiple = true;
    mLoadingFullImage = true;
    getWindow()->incBusyCount();

    LL_DEBUGS("FileSaveAs") << "Scheduling saving file to " << mSaveFileName << LL_ENDL;

    mImage->forceToSaveRawImage(0);//re-fetch the raw image if the old one is removed.
    mImage->setLoadedCallback(LLPreviewTexture::onFileLoadedForSave,
        0, true, false, new LLUUID(mItemUUID), &mCallbackTextureList);
}

// virtual
void LLPreviewTexture::reshape(S32 width, S32 height, bool called_from_parent)
{
    LLPreview::reshape(width, height, called_from_parent);

    S32 horiz_pad = 2 * (LLPANEL_BORDER_WIDTH + PREVIEW_PAD) + PREVIEW_RESIZE_HANDLE_SIZE;

    // add space for dimensions and aspect ratio
    S32 info_height = CLIENT_RECT_VPAD;

    if (mDimensionsText)
    {
        LLRect dim_rect(mDimensionsText->getRect());
        info_height += dim_rect.mTop;
    }

    if (mButtonsPanel && mButtonsPanel->getVisible())
    {
        info_height += mButtonsPanel->getRect().getHeight();
    }
    LLRect client_rect(horiz_pad, getRect().getHeight(), getRect().getWidth() - horiz_pad, 0);
    client_rect.mTop -= (PREVIEW_HEADER_SIZE + CLIENT_RECT_VPAD);
    client_rect.mBottom += PREVIEW_BORDER + CLIENT_RECT_VPAD + info_height ;

    S32 client_width = client_rect.getWidth();
    S32 client_height = client_rect.getHeight();

    if (mAspectRatio > 0.f)
    {
        if(mAspectRatio > 1.f)
        {
            client_height = llceil((F32)client_width / mAspectRatio);
            if(client_height > client_rect.getHeight())
            {
                client_height = client_rect.getHeight();
                client_width = llceil((F32)client_height * mAspectRatio);
            }
        }
        else//mAspectRatio < 1.f
        {
            client_width = llceil((F32)client_height * mAspectRatio);
            if(client_width > client_rect.getWidth())
            {
                client_width = client_rect.getWidth();
                client_height = llceil((F32)client_width / mAspectRatio);
            }
        }
    }

    mClientRect.setLeftTopAndSize(client_rect.getCenterX() - (client_width / 2), client_rect.getCenterY() +  (client_height / 2), client_width, client_height);

}

// virtual
void LLPreviewTexture::onFocusReceived()
{
    LLPreview::onFocusReceived();
}

void LLPreviewTexture::openToSave()
{
    mPreviewToSave = true;
}

void LLPreviewTexture::hideCtrlButtons()
{
    getChildView("desc txt")->setVisible(false);
    getChildView("desc")->setVisible(false);
    getChild<LLLayoutStack>("preview_stack")->collapsePanel(mButtonsPanel, true);
    mButtonsPanel->setVisible(false);
    getChild<LLComboBox>("combo_aspect_ratio")->setCurrentByIndex(0); //unconstrained
    reshape(getRect().getWidth(), getRect().getHeight());
}

// static
void LLPreviewTexture::onFileLoadedForSave(bool success,
                       LLViewerFetchedTexture *src_vi,
                       LLImageRaw* src,
                       LLImageRaw* aux_src,
                       S32 discard_level,
                       bool final,
                       void* userdata)
{
    LLUUID* item_uuid = (LLUUID*) userdata;

    LLPreviewTexture* self = LLFloaterReg::findTypedInstance<LLPreviewTexture>("preview_texture", *item_uuid);

    if( final || !success )
    {
        delete item_uuid;

        if( self )
        {
            self->getWindow()->decBusyCount();
            self->mLoadingFullImage = false;
        }
        if (!success)
        {
            LL_WARNS("FileSaveAs") << "Failed to download file " << *item_uuid << " for saving."
                << " Is missing: " << (src_vi->isMissingAsset() ? "true" : "false")
                << " Discard: " << src_vi->getDiscardLevel()
                << " Raw discard: " << discard_level
                << " Size: " << src_vi->getWidth() << "x" << src_vi->getHeight()
                << " Has GL texture: " << (src_vi->hasGLTexture() ? "true" : "false")
                << " Has saved raw image: " << (src_vi->hasSavedRawImage() ? "true" : "false") << LL_ENDL;
        }
    }

    if( self && final && success )
    {
        LL_DEBUGS("FileSaveAs") << "Saving file to " << self->mSaveFileName << LL_ENDL;
        const U32 ext_length = 3;
        std::string extension = self->mSaveFileName.substr( self->mSaveFileName.length() - ext_length);

        std::string filepath;
        if (self->mSavingMultiple)
        {
            std::string part_path = self->mSaveFileName.substr(0, self->mSaveFileName.length() - ext_length - 1);

            S32 i = 0;
            S32 err = 0;
            do
            {
                filepath = part_path;

                if (i != 0)
                {
                    filepath += llformat("_%.3d", i);
                }

                filepath += ".";
                filepath += extension;

                llstat stat_info;
                err = LLFile::stat(filepath, &stat_info);
                i++;
            } while (-1 != err);  // Search until the file is not found (i.e., stat() gives an error).
        }
        else
        {
            filepath = self->mSaveFileName;
        }

        LLStringUtil::toLower(extension);
        // We only support saving in PNG or TGA format
        LLPointer<LLImageFormatted> image;
        if(extension == "png")
        {
            image = new LLImagePNG;
        }
        else if(extension == "tga")
        {
            image = new LLImageTGA;
        }

        if( image && !image->encode( src, 0 ) )
        {
            LLSD args;
            args["FILE"] = filepath;
            LLNotificationsUtil::add("CannotEncodeFile", args);
        }
        else if( image && !image->save(filepath) )
        {
            LLSD args;
            args["FILE"] = filepath;
            LLNotificationsUtil::add("CannotWriteFile", args);
        }
        else
        {
            self->mSavedFileTimer.reset();
            self->mSavedFileTimer.setTimerExpirySec( SECONDS_TO_SHOW_FILE_SAVED_MSG );
        }
        LL_DEBUGS("FileSaveAs") << "Done saving file to " << filepath << LL_ENDL;

        self->mSaveFileName.clear();
    }

    if( self && !success )
    {
        LLNotificationsUtil::add("CannotDownloadFile");
    }

}


// It takes a while until we get height and width information.
// When we receive it, reshape the window accordingly.
void LLPreviewTexture::updateDimensions()
{
    if (!mImage)
    {
        return;
    }
    if ((mImage->getFullWidth() * mImage->getFullHeight()) == 0)
    {
        return;
    }

    S32 img_width = mImage->getFullWidth();
    S32 img_height = mImage->getFullHeight();

    if (mAssetStatus != PREVIEW_ASSET_LOADED
        || mLastWidth != img_width
        || mLastHeight != img_height)
    {
        mAssetStatus = PREVIEW_ASSET_LOADED;
        // Asset has been fully loaded, adjust aspect ratio
        adjustAspectRatio();
    }


    // Update the width/height display every time
    mDimensionsText->setTextArg("[WIDTH]", llformat("%d", img_width));
    mDimensionsText->setTextArg("[HEIGHT]", llformat("%d", img_height));

    mLastHeight = img_height;
    mLastWidth = img_width;

    // Reshape the floater only when required
    if (mUpdateDimensions)
    {
        mUpdateDimensions = false;

        //reshape floater
        reshape(getRect().getWidth(), getRect().getHeight());

        gFloaterView->adjustToFitScreen(this, false);

        LLRect dim_rect(mDimensionsText->getRect());
        LLRect aspect_label_rect(mAspectRatioText->getRect());
        mAspectRatioText->setVisible( dim_rect.mRight < aspect_label_rect.mLeft);
    }
}


// Return true if everything went fine, false if we somewhat modified the ratio as we bumped on border values
bool LLPreviewTexture::setAspectRatio(const F32 width, const F32 height)
{
    mUpdateDimensions = true;

    // We don't allow negative width or height. Also, if height is positive but too small, we reset to default
    // A default 0.f value for mAspectRatio means "unconstrained" in the rest of the code
    if ((width <= 0.f) || (height <= F_APPROXIMATELY_ZERO))
    {
        mAspectRatio = 0.f;
        return false;
    }

    // Compute and store the ratio
    F32 ratio = width / height;
    mAspectRatio = llclamp(ratio, PREVIEW_TEXTURE_MIN_ASPECT, PREVIEW_TEXTURE_MAX_ASPECT);

    // Return false if we clamped the value, true otherwise
    return (ratio == mAspectRatio);
}


void LLPreviewTexture::onAspectRatioCommit(LLUICtrl* ctrl, void* userdata)
{
    LLPreviewTexture* self = (LLPreviewTexture*) userdata;

    std::string ratio(ctrl->getValue().asString());
    std::string::size_type separator(ratio.find_first_of(":/\\"));

    if (std::string::npos == separator) {
        // If there's no separator assume we want an unconstrained ratio
        self->setAspectRatio( 0.f, 0.f );
        return;
    }

    F32 width, height;
    std::istringstream numerator(ratio.substr(0, separator));
    std::istringstream denominator(ratio.substr(separator + 1));
    numerator >> width;
    denominator >> height;

    self->setAspectRatio( width, height );
}

void LLPreviewTexture::loadAsset()
{
    mImage = LLViewerTextureManager::getFetchedTexture(mImageID, FTT_DEFAULT, MIPMAP_TRUE, LLGLTexture::BOOST_NONE, LLViewerTexture::LOD_TEXTURE);
    mImageOldBoostLevel = mImage->getBoostLevel();
    mImage->setBoostLevel(LLGLTexture::BOOST_PREVIEW);
    mImage->forceToSaveRawImage(0) ;
    mAssetStatus = PREVIEW_ASSET_LOADING;
    mUpdateDimensions = true;
    updateDimensions();
    getChildView("save_tex_btn")->setEnabled(canSaveAs());
    if (mObjectUUID.notNull())
    {
        // check that we can copy inworld items into inventory
        getChildView("Keep")->setEnabled(mIsCopyable);
    }
    else
    {
        // check that we can remove item
        bool source_library = gInventory.isObjectDescendentOf(mItemUUID, gInventory.getLibraryRootFolderID());
        if (source_library)
        {
            getChildView("Discard")->setEnabled(false);
        }
    }
}

LLPreview::EAssetStatus LLPreviewTexture::getAssetStatus()
{
    if (mImage.notNull() && (mImage->getFullWidth() * mImage->getFullHeight() > 0))
    {
        mAssetStatus = PREVIEW_ASSET_LOADED;
    }
    return mAssetStatus;
}

void LLPreviewTexture::adjustAspectRatio()
{
    S32 w = mImage->getFullWidth();
    S32 h = mImage->getFullHeight();

    // Determine aspect ratio of the image
    S32 tmp;
    while (h != 0)
    {
        tmp = w % h;
        w = h;
        h = tmp;
    }
    S32 divisor = w;
    S32 num = mImage->getFullWidth() / divisor;
    S32 denom = mImage->getFullHeight() / divisor;

    if (setAspectRatio((F32)num, (F32)denom))
    {
        // Select corresponding ratio entry in the combo list
        LLComboBox* combo = getChild<LLComboBox>("combo_aspect_ratio");
        if (combo)
        {
            std::ostringstream ratio;
            ratio << num << ":" << denom;
            std::vector<std::string>::const_iterator found = std::find(mRatiosList.begin(), mRatiosList.end(), ratio.str());
            if (found == mRatiosList.end())
            {
                // No existing ratio found, create an element that will show image at original ratio
                populateRatioList(); // makes sure previous custom ratio is cleared
                std::string ratio = std::to_string(num)+":" + std::to_string(denom);
                mRatiosList.push_back(ratio);
                combo->add(ratio);
                combo->setCurrentByIndex(static_cast<S32>(mRatiosList.size()) - 1);
            }
            else
            {
                combo->setCurrentByIndex((S32)(found - mRatiosList.begin()));
            }
        }
    }
    else
    {
        // Aspect ratio was set to unconstrained or was clamped
        LLComboBox* combo = getChild<LLComboBox>("combo_aspect_ratio");
        if (combo)
        {
            combo->setCurrentByIndex(0); //unconstrained
        }
    }

    mUpdateDimensions = true;
}

void LLPreviewTexture::updateImageID()
{
    const LLViewerInventoryItem *item = static_cast<const LLViewerInventoryItem*>(getItem());
    if(item)
    {
        mImageID = item->getAssetUUID();

        // here's the old logic...
        //mShowKeepDiscard = item->getPermissions().getCreator() != gAgent.getID();
        // here's the new logic... 'cos we hate disappearing buttons.
        mShowKeepDiscard = true;

        mCopyToInv = false;
        LLPermissions perm(item->getPermissions());
        mIsCopyable = perm.allowCopyBy(gAgent.getID(), gAgent.getGroupID()) && perm.allowTransferTo(gAgent.getID());
        mIsFullPerm = item->checkPermissionsSet(PERM_ITEM_UNRESTRICTED);
    }
    else // not an item, assume it's an asset id
    {
        mImageID = mItemUUID;
        mShowKeepDiscard = false;
        mCopyToInv = true;
        mIsCopyable = true;
        mIsFullPerm = true;
    }

}

/* virtual */
void LLPreviewTexture::setObjectID(const LLUUID& object_id)
{
    mObjectUUID = object_id;

    const LLUUID old_image_id = mImageID;

    // Update what image we're pointing to, such as if we just specified the mObjectID
    // that this mItemID is part of.
    updateImageID();

    // If the imageID has changed, start over and reload the new image.
    if (mImageID != old_image_id)
    {
        mAssetStatus = PREVIEW_ASSET_UNLOADED;
        loadAsset();
    }
    refreshFromItem();
}