Unsolved How to save images in a different format
-
Hi everyone!
my problem is that i am using 'save(const QString&, const char*)' function to save the image in another format but it doesn't work properly !
the difference between the original and the save image is obviouse but the extention still the same!!
i have a problem on my computer or i didn't understand what the 'save' function does?? -
Hi and welcome to devnet,
What code are you using ?
What version of Qt are you using ?
What OS are you running ?
What compiler are you using ?
What image format do you have as input ?
What image format are you trying to have as output ?
What is the exact error you have ?
What output are you expecting ?
What output are you getting ? -
i am programming in C++ language , Qt 4.11.1 , on Windows 7, i am using Qt 5.14.2 MinGW 64 bit, input format (png, jpg, jpeg, gif), just(jpeg) as output, i did not have error or either warning , images are being saved succecfully but its not changing the format !
-
@kosai Please show your code
-
void Mwindow::NvlElem(void) { QDir::setCurrent(m_ImgDir);//setting the Directory file if(!Line->text().isEmpty()) { //if user write name of object //List->addItem(Line->text()); List->addItem(Line->text()); //** if(List->count() == 1) List->setCurrentRow(0); return; } //get Image QString ImgDir = QFileDialog::getOpenFileName(this, "Ouvrir un fichier", QString(), "Images (*.png *.gif *.jpg *.jpeg)"); //--Display Img on Tab ImgPixmap->load(ImgDir); ImgWin->setPixmap(*ImgPixmap); //--save Img in Items Image->load(ImgDir); QString ImgExt(ImgDir.right(4)), RImgName, ImgName; if(ImgExt[0] != ".") ImgExt = ImgDir.right(5); //get extention //--i did not find a better way to get extention ! for (int i(ImgDir.length()); i >= 0; i--) { if(ImgDir[i] == "/") break; RImgName += ImgDir[i]; } for(int i(RImgName.length()-1); i >= 0; i--) { if(RImgName[i] == ".") break; ImgName += RImgName[i]; } //--here is the prblm !!!! if(Image->save(ImgName+ImgExt, "png")) { List->addItem(ImgName); } //* if(List->count() == 1) List->setCurrentRow(0); //*****tring another way using QImageWriter but it doesnt work either! ImgWriter->setFileName(ImgName); Line->setText(ImgWriter->fileName()); }
-
The format is 'PNG', not 'png'.
The extension can be retrieved via QFileInfo and there is no need to create a QImage with new. -
ok!
i tried "PNG" its the same problem ! -
@kosai In your first post you wrote: "but the extention still the same". This is a different problem than "but its not changing the format". So, did you make sure the format was indeed not changed?
-
the problem is a little bit bizzard !
it's like changing bytes into the desired format --> if you put saved image with the original you will distinguish the diffrence !
but unlike if you go to the file on the desktop the extention doesn't change at all !!
i hope this helps to understand my problem? -
@kosai said in How to save images in a different format:
i hope this helps to understand my problem?
Not really.
What exactly is the problem:- Wrong file extension?
- File is not stored as png?
Please be more clear.
If the file extension is not what you want then check your code and use @Christian-Ehrlicher suggested to get file extension. -
@kosai said in How to save images in a different format:
ile on the desktop the extention doesn't change at all !!
why should the extension change ? you extract it from the select file
QString ImgExt(ImgDir.right(4)), RImgName, ImgName; if(ImgExt[0] != ".") ImgExt = ImgDir.right(5);
and than append it again to the filename when you save it
Image->save(ImgName+ImgExt, "png")
without changing it in-between, of course it will have the same extension.
-
yeah! you are right i shouldn't put the original extention with the name !
thank you everyone ! -
Another issue in your code, why are you forcing the output to be PNG and yet allow other extensions ? That does not really make sense. Personally I would be very surprised to find PNG while opening for example a .bmp file.