webp_clr.cpp

// This is the main DLL file.

#include "stdafx.h"

array<Byte>^ WebPCLR::Encoder::Encode(Bitmap^ bmp, float quality) {
	Rectangle bounds = Rectangle(0, 0, bmp->Width, bmp->Height);
	Imaging::BitmapData^ bmpdata = bmp->LockBits(bounds, Imaging::ImageLockMode::ReadOnly, Imaging::PixelFormat::Format32bppArgb);
	IntPtr argb = bmpdata->Scan0;


	WebPConfig cfg;
	WebPConfigPreset(&cfg, WEBP_PRESET_DEFAULT, quality);
	//WebPConfigInit(&cfg);
	cfg.method = 6;

	if (WebPValidateConfig(&cfg) == false) {
		throw gcnew System::Exception("WebP config validation failed (invalid quality?)");
	}

	WebPPicture webp;
	if (WebPPictureInit(&webp) == false) {
		throw gcnew Exception("Unable to initialize WebPPicture data structure (version mismatch?)");
	}
	webp.width = bmp->Width;
	webp.height = bmp->Height;
	webp.use_argb = true;
	if (WebPPictureAlloc(&webp) == false) {
		throw gcnew Exception("Unable to allocate memory: WebPPictureAlloc() returned FALSE)");
	}

	// Copy RGBA bitmap data
	//WebPPictureImportRGBA(&webp, (uint8_t*)((void*)argb), bmpdata->Stride);
	webp.argb = (uint32_t*)((void*)argb);
	webp.argb_stride = bmpdata->Stride / sizeof(uint32_t); // Convert BitmapData stride (bytes) to webp (pixels)

	WebPMemoryWriter writer;
	WebPMemoryWriterInit(&writer);
	webp.writer = WebPMemoryWrite;
	webp.custom_ptr = &writer;

	int status = WebPEncode(&cfg, &webp);
	WebPPictureFree(&webp);
	bmp->UnlockBits(bmpdata);
	if (!status) {
		throw gcnew Exception(String::Format("WebPEncode error, code: {0}", (int)webp.error_code));
	}

	array<Byte>^ buf = gcnew array<Byte>(writer.size);
	System::Runtime::InteropServices::Marshal::Copy(IntPtr(writer.mem), buf, 0, writer.size);
	return buf;
}