Convert System::Drawing::Bitmap^ to Pix* (leptonica)
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I have a Bitmap in memory which gets passed into my library from a C# application. I need to convert it into a leptonica Pix* to pass it into tesseract. Conversely, I'm going to have to take the Pix* from the thresholded image and convert it back to a Bitmap to return it to the C# application but I'm not there yet. Here's my code to go from Bitmap to Pix:
Pix* OcrProcessor::ToPix(Bitmap^ bitmap)
const auto rect = new Drawing::Rectangle(0, 0, bitmap->Width, bitmap->Height);
const auto bitmap_data = bitmap->LockBits(*rect, ImageLockMode::ReadOnly, bitmap->PixelFormat);
auto ptr = bitmap_data->Scan0;
const auto bytes = Math::Abs(bitmap_data->Stride) * bitmap->Height;
const auto rgb_values = gcnew array<unsigned char>(bytes);
Marshal::Copy(ptr, rgb_values, 0, bytes);
auto handle = GCHandle::Alloc(rgb_values, GCHandleType::Pinned);
const auto data = static_cast<unsigned char*>(static_cast<void*>(handle.AddrOfPinnedObject()));
const auto converted = pixReadMemBmp(data, bytes);
bitmap->UnlockBits(bitmap_data);
delete rect;
return converted;
The Pix* converted is always null at the end. Stepping through the code, rgb_values is always an array filled with 255 throughout instead of being filled with the bitmap data. I'm not heavily invested in this particular method, if anyone has a working method to accomplish what I'm looking for.
visual-c++ c++-cli leptonica
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
add a comment |
I have a Bitmap in memory which gets passed into my library from a C# application. I need to convert it into a leptonica Pix* to pass it into tesseract. Conversely, I'm going to have to take the Pix* from the thresholded image and convert it back to a Bitmap to return it to the C# application but I'm not there yet. Here's my code to go from Bitmap to Pix:
Pix* OcrProcessor::ToPix(Bitmap^ bitmap)
const auto rect = new Drawing::Rectangle(0, 0, bitmap->Width, bitmap->Height);
const auto bitmap_data = bitmap->LockBits(*rect, ImageLockMode::ReadOnly, bitmap->PixelFormat);
auto ptr = bitmap_data->Scan0;
const auto bytes = Math::Abs(bitmap_data->Stride) * bitmap->Height;
const auto rgb_values = gcnew array<unsigned char>(bytes);
Marshal::Copy(ptr, rgb_values, 0, bytes);
auto handle = GCHandle::Alloc(rgb_values, GCHandleType::Pinned);
const auto data = static_cast<unsigned char*>(static_cast<void*>(handle.AddrOfPinnedObject()));
const auto converted = pixReadMemBmp(data, bytes);
bitmap->UnlockBits(bitmap_data);
delete rect;
return converted;
The Pix* converted is always null at the end. Stepping through the code, rgb_values is always an array filled with 255 throughout instead of being filled with the bitmap data. I'm not heavily invested in this particular method, if anyone has a working method to accomplish what I'm looking for.
visual-c++ c++-cli leptonica
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
That function looks pretty funky, pixReadMemBmp() needs to know how the bitmap is organized to interpret the pixel data correctly. The pixel format matters a lot. Its implementation is not encouraging. But unsurprising. If you can't find a better way in that library then you may have to save it to a temp file.
– Hans Passant
Nov 15 '18 at 15:34
add a comment |
I have a Bitmap in memory which gets passed into my library from a C# application. I need to convert it into a leptonica Pix* to pass it into tesseract. Conversely, I'm going to have to take the Pix* from the thresholded image and convert it back to a Bitmap to return it to the C# application but I'm not there yet. Here's my code to go from Bitmap to Pix:
Pix* OcrProcessor::ToPix(Bitmap^ bitmap)
const auto rect = new Drawing::Rectangle(0, 0, bitmap->Width, bitmap->Height);
const auto bitmap_data = bitmap->LockBits(*rect, ImageLockMode::ReadOnly, bitmap->PixelFormat);
auto ptr = bitmap_data->Scan0;
const auto bytes = Math::Abs(bitmap_data->Stride) * bitmap->Height;
const auto rgb_values = gcnew array<unsigned char>(bytes);
Marshal::Copy(ptr, rgb_values, 0, bytes);
auto handle = GCHandle::Alloc(rgb_values, GCHandleType::Pinned);
const auto data = static_cast<unsigned char*>(static_cast<void*>(handle.AddrOfPinnedObject()));
const auto converted = pixReadMemBmp(data, bytes);
bitmap->UnlockBits(bitmap_data);
delete rect;
return converted;
The Pix* converted is always null at the end. Stepping through the code, rgb_values is always an array filled with 255 throughout instead of being filled with the bitmap data. I'm not heavily invested in this particular method, if anyone has a working method to accomplish what I'm looking for.
visual-c++ c++-cli leptonica
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
I have a Bitmap in memory which gets passed into my library from a C# application. I need to convert it into a leptonica Pix* to pass it into tesseract. Conversely, I'm going to have to take the Pix* from the thresholded image and convert it back to a Bitmap to return it to the C# application but I'm not there yet. Here's my code to go from Bitmap to Pix:
Pix* OcrProcessor::ToPix(Bitmap^ bitmap)
const auto rect = new Drawing::Rectangle(0, 0, bitmap->Width, bitmap->Height);
const auto bitmap_data = bitmap->LockBits(*rect, ImageLockMode::ReadOnly, bitmap->PixelFormat);
auto ptr = bitmap_data->Scan0;
const auto bytes = Math::Abs(bitmap_data->Stride) * bitmap->Height;
const auto rgb_values = gcnew array<unsigned char>(bytes);
Marshal::Copy(ptr, rgb_values, 0, bytes);
auto handle = GCHandle::Alloc(rgb_values, GCHandleType::Pinned);
const auto data = static_cast<unsigned char*>(static_cast<void*>(handle.AddrOfPinnedObject()));
const auto converted = pixReadMemBmp(data, bytes);
bitmap->UnlockBits(bitmap_data);
delete rect;
return converted;
The Pix* converted is always null at the end. Stepping through the code, rgb_values is always an array filled with 255 throughout instead of being filled with the bitmap data. I'm not heavily invested in this particular method, if anyone has a working method to accomplish what I'm looking for.
visual-c++ c++-cli leptonica
visual-c++ c++-cli leptonica
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
asked Nov 15 '18 at 14:27
Dewey VozelDewey Vozel
992816
992816
That function looks pretty funky, pixReadMemBmp() needs to know how the bitmap is organized to interpret the pixel data correctly. The pixel format matters a lot. Its implementation is not encouraging. But unsurprising. If you can't find a better way in that library then you may have to save it to a temp file.
– Hans Passant
Nov 15 '18 at 15:34
add a comment |
That function looks pretty funky, pixReadMemBmp() needs to know how the bitmap is organized to interpret the pixel data correctly. The pixel format matters a lot. Its implementation is not encouraging. But unsurprising. If you can't find a better way in that library then you may have to save it to a temp file.
– Hans Passant
Nov 15 '18 at 15:34
That function looks pretty funky, pixReadMemBmp() needs to know how the bitmap is organized to interpret the pixel data correctly. The pixel format matters a lot. Its implementation is not encouraging. But unsurprising. If you can't find a better way in that library then you may have to save it to a temp file.
– Hans Passant
Nov 15 '18 at 15:34
That function looks pretty funky, pixReadMemBmp() needs to know how the bitmap is organized to interpret the pixel data correctly. The pixel format matters a lot. Its implementation is not encouraging. But unsurprising. If you can't find a better way in that library then you may have to save it to a temp file.
– Hans Passant
Nov 15 '18 at 15:34
add a comment |
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That function looks pretty funky, pixReadMemBmp() needs to know how the bitmap is organized to interpret the pixel data correctly. The pixel format matters a lot. Its implementation is not encouraging. But unsurprising. If you can't find a better way in that library then you may have to save it to a temp file.
– Hans Passant
Nov 15 '18 at 15:34