While using bitmap in Xamarin Forms Android I'm getting out of memory error while loading images which are of higher than the usual size.
void getImage() {
-------
imageView.setImageBitmap(Bitmap.createScaledBitmap(getBitmapFromViewUpdated(_view), (int) width, (int) height, true));
tempView = imageView;
--------
}
public static Bitmap getBitmapFromView(final View view) {
view.setLayoutParams(new LayoutParams(view.getWidth(),
view.getHeight()));
view.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
final Bitmap bitmap_ = Bitmap
.createBitmap(view.getMeasuredWidth(),
view.getMeasuredHeight(),
Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bitmap_);
view.draw(c);
return bitmap_;
}
Bitmap getBitmapFromViewUpdated(final View view) {
if (view.getWidth() == 0 || view.getHeight() == 0)
view.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT));
else
view.setLayoutParams(new LayoutParams(view.getWidth(),
view.getHeight()));
view.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
view.layout(0, 0, viewWidth, viewHeight);
final Bitmap bitmap_;
if(viewWidth>0 && viewHeight>0) {
bitmap_ = Bitmap
.createBitmap(viewWidth,
viewHeight, Bitmap.Config.ARGB_8888);
}
else
{
bitmap_= Bitmap
.createBitmap(view.getMeasuredWidth(),
view.getMeasuredHeight(),
Bitmap.Config.ARGB_8888);
}
Canvas c = new Canvas(bitmap_);
view.draw(c);
return bitmap_;
}
I have tried android:largeHeap=true, can achieve the result while using that but I need to know how to fix with bitmap resizing.
You can check these two links for efficient bitmap management in xamarin android
https://forums.xamarin.com/discussion/5716/disposing-of-bitmaps-properly
https://developer.xamarin.com/recipes/android/resources/general/load_large_bitmaps_efficiently/
GoodLuck!
Related
I need to change the background color of the currently tabbed page in my UITabBarController. I've searched through every stackoverflow post I could find but nothing worked for me. I thought there would be something like UITabBar.Appearance.SelectedImageTintColor, just for the background color but it doesn't seem so.
For example, I want to change the color of that part when I am on the right tab:
Does someone know how to do that?
You could invoked the following code in your UITabBarController
public xxxTabBarController()
{
//...set ViewControllers
this.TabBar.BarTintColor = UIColor.Red;
}
Update
//3.0 here is if you have three child page in tab , set it as the current value in your project
//
var size = new CGSize(TabBar.Frame.Width / 3.0, IsFullScreen());
this.TabBar.SelectionIndicatorImage = ImageWithColor(size,UIColor.Green);
double IsFullScreen()
{
double height = 64;
if (UIDevice.CurrentDevice.CheckSystemVersion(11, 0))
{
if (UIApplication.SharedApplication.Delegate.GetWindow().SafeAreaInsets.Bottom > 0.0)
{
height = 84;
}
}
return height;
}
UIImage ImageWithColor(CGSize size, UIColor color)
{
var rect = new CGRect(0, 0, size.Width, size.Height);
UIGraphics.BeginImageContextWithOptions(size, false, 0);
CGContext context = UIGraphics.GetCurrentContext();
context.SetFillColor(color.CGColor);
context.FillRect(rect);
UIImage image = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
return image;
}
The trick is to use the SelectionIndicatorImage Property of the UITabBar and generate a completely filled image with your desired color using the following method:
private UIImage ImageWithColor(CGSize size)
{
CGRect rect = new CGRect(0, 0, size.Width, size.Height);
UIGraphics.BeginImageContext(size);
using (CGContext context = UIGraphics.GetCurrentContext())
{
context.SetFillColor(UIColor.Green); //change color if necessary
context.FillRect(rect);
}
UIImage image = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
return image;
}
To initialize everything we override ViewWillLayoutSubviews() like this:
public override void ViewWillLayoutSubviews()
{
base.ViewWillLayoutSubviews();
// The tabbar height will always be 49 unless we force it to reevaluate it's size on runtime ...
myTabBar.InvalidateIntrinsicContentSize();
double height = myTabBar.Frame.Height;
CGSize size = new CGSize(new nfloat(myTabBar.Frame.Width / myTabBar.Items.Length, height));
// Now get our all-green image...
UIImage image = ImageWithColor(size);
// And set it as the selection indicator
myTabBar.SelectionIndicatorImage = image;
}
As mentioned in this article (google translating it step by step when necessary lol) calling InvalidateIntrinsicContentSize() will force the UITabBar to reevaluate it's size and will get you the actual runtime height of the tab bar (instead of the constant 49 height value from XCode).
How can I draw an OCX (I do have the sources) to an CBitmap-Object or something alike?
Background: My client creates PDF-Documents and part of these documents is an Output from an OCX. The PDF-lib-Interface has a Method to put an Image from an CBitmap-Object to the PDF-Page.
So what i want to do ist let the Program create an CBitmap-Object, pass that to the OCX to let it draw its content onto it and then pass the he CBitmap to the PDF-library to get it into the document.
So the main question is: how to draw my ocx into a CBitmap-Object?
I'm using Visual C++, Windows, MFC/ATL.
Thanks a lot
actually I didn't manage to render the OXC to a CBitmap (just got a black box drawn) but rendering into an ATL::CImage and making a CBitmap out of it worked:
ATL::CImage* CPrnBasePrinter::DrawBeamerToImage(CSPCListView* pListViewWithBeamer, const CRect& rect4Beamer)
{
ASSERT(pListViewWithBeamer != nullptr);
auto* pRetVal = new CImage();
pRetVal->Create(rect4Beamer.Width(), rect4Beamer.Height(), 24);
HDC hdcImage = pRetVal->GetDC();
//Draw Control to CImage
pListViewWithBeamer->DrawBeamerToDC(HandleToLong(hdcImage),
rect4Beamer.left, rect4Beamer.top, rect4Beamer.right, rect4Beamer.bottom);
pRetVal->ReleaseDC();
return pRetVal;
}
void CPrnBasePrinter::DrawImageFromCImage(
const ATL::CImage* pImage, const CRect& rect) const
{
CBitmap* pbmp2Print = CBitmap::FromHandle(*pImage);
// Get the size of the bitmap
BITMAP bmpInfo;
pbmp2Print->GetBitmap(&bmpInfo);
//virtual - Draws the CBitmap to an Printer-DC or a PDF-Document
DrawImageFromLoadedBitmap(pbmp2Print, &bmpInfo, rect);
}
void CPrnBasePrinter::Draw()
{
//m_pListviewDataSource is an OCX capable of drawing itself into a given DC
ATL::CImage* pBeamerImage = DrawBeamerToImage(m_pListviewDataSource, CRect(0, 0, 100, 50));
if (pBeamerImage != nullptr){
DrawImageFromCImage(pBeamerImage, CRect(0, 0, 100, 50));
delete pBeamerImage;
}
}
My iOS 6 code to show the camera in a UIPopoverController works fine but iOS won't scale the camera view. Please see images below. Any suggestions would be appreciated.
Edit
public class NoRotationUIImagePickerController : UIImagePickerController
{
public override bool ShouldAutorotate ()
{
return false;
}
}
//place imagePicker into a container so that we can control the size of the popover
container = new UIViewController();
container.ContentSizeForViewInPopover = new SizeF(parentViewController.View.Frame.Width, parentViewController.View.Frame.Height);
container.View.AddSubview(_imagePicker.View);
_popOver = new UIPopoverController (container);
//If no camera is available, return false and do nothing.
if (IsCameraHardwareAvailable())
{
_imagePicker.Delegate = new PopUpGalleryPickerDelegate (_popOver, _imageSelected);
_imagePicker.SourceType = UIImagePickerControllerSourceType.Camera;
_imagePicker.AllowsEditing = false;
_imagePicker.MediaTypes = new string[] {"public.image"};
RectangleF popRectangle = new RectangleF (new PointF(parentViewController.View.Frame.Width/2, parentViewController.View.Frame.Height/2), new SizeF (1, 1));
_popOver.PresentFromRect(popRectangle, parentViewController.View, 0, true);
_imagePicker.View.Frame = container.View.Frame; //change to frame must come after popover is presented.
}
else
{
cameraAvailable = false;
}
The solution I ended up with was to make the camera full screen instead of using a popover controller.
I'm programming in j2me.
How can I prevent screen rotation in j2me for all phones that support screen rotation?
thanks.
If you use Canvas to draw your screen (not LCDUI, not LWUIT, not any other framework) you may implement sizeChanged method to be notified when the rotation happens.
In such case you may draw your screen to an Image and use Sprite to rotate it. For example, to support only Landscape mode I used below code at constructor:
int width = Math.max(super.getWidth(), super.getHeight());
int height = Math.min(super.getWidth(), super.getHeight());
// screen and sprite are attributes
screen = Image.createImage(width, height);
sprite = new Sprite(screen);
if (super.getWidth() < super.getHeight()) { // portrait screen
sprite.setTransform(Sprite.TRANS_ROT90);
sprite.setPosition(0, 0);
}
And following methods:
public void sizeChanged (int w, int h) {
// lastWidth and lastHeight are attributes
lastWidth = w;
lastHeight = h;
if (sprite == null) return;
if (super.getWidth() < super.getHeight()) { // portrait screen
sprite.setTransform(Sprite.TRANS_ROT90);
} else {
sprite.setTransform(Sprite.TRANS_NONE);
}
sprite.setPosition(0, 0);
}
protected void paint(Graphics g1) {
if (super.getWidth() != lastWidth
|| super.getHeight() != lastHeight) {
sizeChanged(super.getWidth(), super.getHeight());
}
Graphics g = screen.getGraphics();
// ... do your drawing on g
this.sprite.setImage(screen, screen.getWidth(), screen.getHeight());
sprite.paint(g1);
}
As seen at http://smallandadaptive.blogspot.com.br/2009/08/fullscreen-landscape.html and http://smallandadaptive.blogspot.com.br/2010/03/adapting-to-sizechanged.html and http://smallandadaptive.blogspot.com.br/2011/04/sizechanged-not-called.html
Add to manifest
For Nokia devices:
Nokia-MIDlet-App-Orientation : Landscape
For Samsung devices:
MIDlet-ScreenMode : Landscape
I wanted to know if we can resize an image. Suppose if we want to draw an image of 200x200 actual size with a size of 100 x 100 size on our blackberry screen.
Thanks
You can do this pretty simply using the EncodedImage.scaleImage32() method. You'll need to provide it with the factors by which you want to scale the width and height (as a Fixed32).
Here's some sample code which determines the scale factor for the width and height by dividing the original image size by the desired size, using RIM's Fixed32 class.
public static EncodedImage resizeImage(EncodedImage image, int newWidth, int newHeight) {
int scaleFactorX = Fixed32.div(Fixed32.toFP(image.getWidth()), Fixed32.toFP(newWidth));
int scaleFactorY = Fixed32.div(Fixed32.toFP(image.getHeight()), Fixed32.toFP(newHeight));
return image.scaleImage32(scaleFactorX, scaleFactorY);
}
If you're lucky enough to be developer for OS 5.0, Marc posted a link to the new APIs that are a lot clearer and more versatile than the one I described above. For example:
public static Bitmap resizeImage(Bitmap originalImage, int newWidth, int newHeight) {
Bitmap newImage = new Bitmap(newWidth, newHeight);
originalImage.scaleInto(newImage, Bitmap.FILTER_BILINEAR, Bitmap.SCALE_TO_FILL);
return newImage;
}
(Naturally you can substitute the filter/scaling options based on your needs.)
Just an alternative:
BlackBerry - draw image on the screen
BlackBerry - image 3D transform
I'm not a Blackberry programmer, but I believe some of these links will help you out:
Image Resizing Article
Resizing a Bitmap on the Blackberry
Blackberry Image Scaling Question
Keep in mind that the default image scaling done by BlackBerry is quite primitive and generally doesn't look very good. If you are building for 5.0 there is a new API to do much better image scaling using filters such as bilinear or Lanczos.
For BlackBerry JDE 5.0 or later, you can use the scaleInto API.
in this there is two bitmap.temp is holding the old bitmap.In this method you just pass
bitmap ,width,height.it return new bitmap of your choice.
Bitmap ImgResizer(Bitmap bitmap , int width , int height){
Bitmap temp=new Bitmap(width,height);
Bitmap resized_Bitmap = bitmap;
temp.createAlpha(Bitmap.HOURGLASS);
resized_Bitmap.scaleInto(temp , Bitmap.FILTER_LANCZOS);
return temp;
}
Here is the function or you can say method to resize image, use it as you want :
int olddWidth;
int olddHeight;
int dispplayWidth;
int dispplayHeight;
EncodedImage ei2 = EncodedImage.getEncodedImageResource("add2.png");
olddWidth = ei2.getWidth();
olddHeight = ei2.getHeight();
dispplayWidth = 40;\\here pass the width u want in pixels
dispplayHeight = 80;\\here pass the height u want in pixels again
int numeerator = net.rim.device.api.math.Fixed32.toFP(olddWidth);
int denoominator = net.rim.device.api.math.Fixed32.toFP(dispplayWidth);
int widtthScale = net.rim.device.api.math.Fixed32.div(numeerator, denoominator);
numeerator = net.rim.device.api.math.Fixed32.toFP(olddHeight);
denoominator = net.rim.device.api.math.Fixed32.toFP(dispplayHeight);
int heighhtScale = net.rim.device.api.math.Fixed32.div(numeerator, denoominator);
EncodedImage newEi2 = ei2.scaleImage32(widtthScale, heighhtScale);
Bitmap _add =newEi2.getBitmap();
I am posting this answers for newbie in Blackberry Application development. Below code is for processing Bitmap images from URL and Resizing them without loass of Aspect Ratio :
public static Bitmap imageFromServer(String url)
{
Bitmap bitmp = null;
try{
HttpConnection fcon = (HttpConnection)Connector.open(url);
int rc = fcon.getResponseCode();
if(rc!=HttpConnection.HTTP_OK)
{
throw new IOException("Http Response Code : " + rc);
}
InputStream httpInput = fcon.openDataInputStream();
InputStream inp = httpInput;
byte[] b = IOUtilities.streamToBytes(inp);
EncodedImage img = EncodedImage.createEncodedImage(b, 0, b.length);
bitmp = resizeImage(img.getBitmap(), 100, 100);
}
catch(Exception e)
{
Dialog.alert("Exception : " + e.getMessage());
}
return bitmp;
}
public static Bitmap resizeImage(Bitmap originalImg, int newWidth, int newHeight)
{
Bitmap scaledImage = new Bitmap(newWidth, newHeight);
originalImg.scaleInto(scaledImage, Bitmap.FILTER_BILINEAR, Bitmap.SCALE_TO_FIT);
return scaledImage;
}
The Method resizeImage is called inside the method imageFromServer(String url).
1) the image from server is processed using EncodedImage img.
2) Bitmap bitmp = resizeImage(img.getBitmap(), 100, 100);
parameters are passed to resizeImage() and the return value from resizeImage() is set to Bitmap bitmp.