将 IWICBtmap 写入文件 - 解析不正确
Writing IWICBtmap to file - incorrect resolution
我有以下代码,我在其中读取图像(JPG 进行测试),指定一个剪切矩形区域并将"剪切"区域写入文件。
我的测试图像是 320 x 240 像素 @ 300dpi。当我在所有迹象中阅读它时,它都是那个大小,但是当我写出来时,结果图像是 102 x 76 并且查看文件属性,我没有看到 H/V 分辨率。
现在 320/102 = 3.1372 和 300/96 = 3.125 那么屏幕分辨率与图像有什么关系吗?
写出IWICBitmap的整个主题从一开始就是一场拳击比赛。为什么这么难?
谢谢一堆
IWICImagingFactory *pImageFactory = GfxAgent::WICImagingFactory::GetInstance().GetFactory();
D2D1_SIZE_U sizeFrame = D2D1::SizeU(imageRect.Width(), imageRect.Height());
CComPtr<IWICBitmap> pWICBitmap;
hr = pImageFactory->CreateBitmap(imageRect.Width(), imageRect.Height(),
GUID_WICPixelFormat32bppPBGRA,
WICBitmapCacheOnLoad,
&pWICBitmap
);
D2D1_RENDER_TARGET_PROPERTIES rtProps = D2D1::RenderTargetProperties();
rtProps.pixelFormat = D2D1::PixelFormat(DXGI_FORMAT_B8G8R8A8_UNORM, D2D1_ALPHA_MODE_PREMULTIPLIED);
rtProps.type = D2D1_RENDER_TARGET_TYPE_DEFAULT;
rtProps.usage = D2D1_RENDER_TARGET_USAGE_NONE;
// define the render target
CComPtr<ID2D1RenderTarget> pRenderTarget = 0;
hr = m_pDirect2dFactory->CreateWicBitmapRenderTarget(pWICBitmap, rtProps, &pRenderTarget);
CComPtr<ID2D1Bitmap> imageS;
hr = GfxAgent::ImageUtilities::LoadImageFromFile(pRenderTarget, m_imgPath, 0, 0, 0, &imageS, &resX, &resY);
if (hr != S_OK)
{
}
// get format of image we just read
D2D1_PIXEL_FORMAT fmt = imageS->GetPixelFormat();
CComPtr<ID2D1Bitmap> imageD;
D2D1_SIZE_U bitmapPixelSize = D2D1::SizeU(imageRect.Width(), imageRect.Height());
// create destination image of "clipped" source image
hr = pRenderTarget->CreateBitmap(bitmapPixelSize, D2D1::BitmapProperties(
D2D1::PixelFormat(fmt.format, fmt.alphaMode),
(float)resX, (float)resY), &imageD);
D2D1_POINT_2U topleft = D2D1::Point2U(0, 0);
D2D1_RECT_U srcRect = D2D1::RectU(imageRect.left, imageRect.top, imageRect.right, imageRect.bottom);
// get the "clipped" source
hr = imageD->CopyFromBitmap(&topleft, imageS, &srcRect);
if (hr != S_OK)
{
}
CComPtr<IWICBitmapEncoder> pEncoder;
CComPtr<IWICBitmapFrameEncode> pFrame;
CComPtr<IWICStream> pStream;
WICPixelFormatGUID format = GUID_WICPixelFormat32bppPBGRA;
// draw the "clipped" image into the render target (WIC image)
if (SUCCEEDED(hr)) {
pRenderTarget->BeginDraw();
pRenderTarget->Clear();
pRenderTarget->DrawBitmap(imageD);
hr = pRenderTarget->EndDraw();
}
// now proceed to write the "clipped" image to a file
if (SUCCEEDED(hr)) {
hr = pImageFactory->CreateStream(&pStream);
}
if (SUCCEEDED(hr)) {
hr = pStream->InitializeFromFilename(MultiByteToUnicode(szNewFileName).c_str(), GENERIC_WRITE);
}
if (SUCCEEDED(hr)) {
hr = pImageFactory->CreateEncoder(GUID_ContainerFormatJpeg, NULL, &pEncoder);
}
if (SUCCEEDED(hr)) {
hr = pEncoder->Initialize(pStream, WICBitmapEncoderNoCache);
}
if (SUCCEEDED(hr)) {
hr = pEncoder->CreateNewFrame(&pFrame, NULL);
}
if (SUCCEEDED(hr)) {
hr = pFrame->Initialize(NULL);
}
if (SUCCEEDED(hr)) {
hr = pFrame->SetSize((UINT)imageD->GetSize().width, (UINT)imageD->GetSize().height);
}
if (SUCCEEDED(hr)) {
hr = pFrame->SetPixelFormat(&format);
}
if (SUCCEEDED(hr)) {
hr = pFrame->WriteSource(pWICBitmap, NULL);
}
if (SUCCEEDED(hr)) {
hr = pFrame->Commit();
}
if (SUCCEEDED(hr)) {
hr = pEncoder->Commit();
}
更多信息
D2D1_POINT_2U topleft = D2D1::Point2U(0, 0);
D2D1_RECT_U srcRect = D2D1::RectU(imageRect.left, imageRect.top, imageRect.right, imageRect.bottom);
// get the "clipped" source
hr = imageD->CopyFromBitmap(&topleft, imageS, &srcRect);
if (hr != S_OK)
{
}
UINT wD, hD;
wD = (UINT)imageD->GetSize().width;
hD = (UINT)imageD->GetSize().height;
图像矩形是正确的 LTRB = 0,0,320,240
但在复制后 wD = 102 和 hD = 76
为什么?
以下是更多信息
CComPtr<ID2D1Bitmap> imageD;
D2D1_SIZE_U bitmapPixelSize = D2D1::SizeU(imageRect.Width(), imageRect.Height());
// create destination image of "clipped" source image
hr = pRenderTarget->CreateBitmap(bitmapPixelSize, D2D1::BitmapProperties(
D2D1::PixelFormat(fmt.format, fmt.alphaMode),
(float)resX, (float)resY), &imageD);
UINT wD, hD;
wD = (UINT)imageD->GetSize().width;
hD = (UINT)imageD->GetSize().height;
位图PixelSize是正确的320 x 240,resX和Y是300
format= DXGI_FORMAT_B8G8R8A8_UNORM
alphaMode D2D1_ALPHA_MODE_PREMULTIPLIED
wD = 102 和 hD = 76 - 为什么?
最新代码
IWICImagingFactory *pImageFactory = GfxAgent::WICImagingFactory::GetInstance().GetFactory();
D2D1_SIZE_U sizeFrame = D2D1::SizeU(imageRect.Width(), imageRect.Height());
CComPtr<IWICBitmap> pWICBitmap;
hr = pImageFactory->CreateBitmap(imageRect.Width(), imageRect.Height(),
GUID_WICPixelFormat32bppPBGRA,
WICBitmapCacheOnLoad,
&pWICBitmap
);
// sanity check
UINT wicW, wicH;
pWICBitmap->GetSize(&wicW, &wicH);
D2D1_RENDER_TARGET_PROPERTIES rtProps = D2D1::RenderTargetProperties();
rtProps.pixelFormat = D2D1::PixelFormat(DXGI_FORMAT_B8G8R8A8_UNORM, D2D1_ALPHA_MODE_PREMULTIPLIED);
rtProps.type = D2D1_RENDER_TARGET_TYPE_DEFAULT;
rtProps.usage = D2D1_RENDER_TARGET_USAGE_NONE;
// define the render target
CComPtr<ID2D1RenderTarget> pRenderTarget = 0;
hr = m_pDirect2dFactory->CreateWicBitmapRenderTarget(pWICBitmap, rtProps, &pRenderTarget);
CComPtr<ID2D1Bitmap> imageS;
hr = GfxAgent::ImageUtilities::LoadImageFromFile(pRenderTarget, m_imgPath, 0, 0, 0, &imageS, &resX, &resY);
if (hr != S_OK)
{
}
// set new image resolution same as source
pWICBitmap->SetResolution(resX, resY);
// get format of image we just read
D2D1_PIXEL_FORMAT fmt = imageS->GetPixelFormat();
CComPtr<ID2D1Bitmap> imageD;
D2D1_SIZE_U bitmapPixelSize = D2D1::SizeU(imageRect.Width(), imageRect.Height());
// create destination image of "clipped" source image
hr = pRenderTarget->CreateBitmap(bitmapPixelSize, D2D1::BitmapProperties(
D2D1::PixelFormat(fmt.format, fmt.alphaMode),
(float)resX, (float)resY), &imageD);
D2D1_POINT_2U topleft = D2D1::Point2U(0, 0);
D2D1_RECT_U srcRect = D2D1::RectU(imageRect.left, imageRect.top, imageRect.right, imageRect.bottom);
// get the "clipped" source
hr = imageD->CopyFromBitmap(&topleft, imageS, &srcRect);
if (hr != S_OK)
{
}
// just a sanity check (pixels NOT DIPS)
D2D1_SIZE_U sourcePixelSize = imageS->GetPixelSize();
D2D1_SIZE_U destPixelSize = imageD->GetPixelSize();
CComPtr<IWICBitmapEncoder> pEncoder;
CComPtr<IWICBitmapFrameEncode> pFrame;
CComPtr<IWICStream> pStream;
WICPixelFormatGUID format = GUID_WICPixelFormat32bppPBGRA;
// draw the "clipped" image into the render target (WIC image)
if (SUCCEEDED(hr)) {
pRenderTarget->BeginDraw();
pRenderTarget->Clear();
pRenderTarget->DrawBitmap(imageD);
hr = pRenderTarget->EndDraw();
}
// now proceed to write the "clipped" image to a file
if (SUCCEEDED(hr)) {
hr = pImageFactory->CreateStream(&pStream);
}
if (SUCCEEDED(hr)) {
hr = pStream->InitializeFromFilename(MultiByteToUnicode(szNewFileName).c_str(), GENERIC_WRITE);
}
if (SUCCEEDED(hr)) {
hr = pImageFactory->CreateEncoder(GUID_ContainerFormatJpeg, NULL, &pEncoder);
}
if (SUCCEEDED(hr)) {
hr = pEncoder->Initialize(pStream, WICBitmapEncoderNoCache);
}
if (SUCCEEDED(hr)) {
hr = pEncoder->CreateNewFrame(&pFrame, NULL);
}
if (SUCCEEDED(hr)) {
hr = pFrame->Initialize(NULL);
}
if (SUCCEEDED(hr)) {
hr = pFrame->SetSize(destPixelSize.width, destPixelSize.height);
}
if (SUCCEEDED(hr)) {
hr = pFrame->SetPixelFormat(&format);
}
if (SUCCEEDED(hr)) {
hr = pFrame->WriteSource(pWICBitmap, NULL);
}
if (SUCCEEDED(hr)) {
hr = pFrame->Commit();
}
if (SUCCEEDED(hr)) {
hr = pEncoder->Commit();
}
ID2D1Bitmap::GetSize
让你得到DIPs:
返回位图的大小(以与设备无关的像素 (DIP) 为单位)。
DIP 是 1/96 英寸。若要检索以设备像素为单位的大小,请使用 ID2D1Bitmap::GetPixelSize 方法。
在您的情况下,大小为 320 像素 * 96 dpi/px/300 dpi = 102.4 与设备无关的像素。沿 Y 轴相同。
当我从 WICBitmap 创建呈现器目标时,知道原始图像的分辨率是多少,我使用了以下属性
D2D1_RENDER_TARGET_PROPERTIES rtProps = D2D1::RenderTargetProperties();
rtProps.pixelFormat = D2D1::PixelFormat(DXGI_FORMAT_B8G8R8A8_UNORM, D2D1_ALPHA_MODE_PREMULTIPLIED);
rtProps.type = D2D1_RENDER_TARGET_TYPE_DEFAULT;
rtProps.usage = D2D1_RENDER_TARGET_USAGE_NONE;
rtProps.dpiX = (float)m_img.GetResolutionX();
rtProps.dpiY = (float)m_img.GetResolutionY();
关键是在创建中使用原始图像的分辨率,稍后尝试设置它们没有任何作用。罗曼给了我"提示"——谢谢
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