Add support for Sixel images in conhost

.github/actions/spelling/expect/expect.txt

@@ -116,13 +116,16 @@
 binskim
 bitcoin
 bitcrazed
+BITMAPINFO
+BITMAPINFOHEADER
 bitmasks
 BITOPERATION
 BKCOLOR
 BKGND
 Bksp
 Blt
 BLUESCROLL
+bmi
 BODGY
 BOLDFONT
 Borland
@@ -394,6 +397,11 @@
 DECFI
 DECFNK
 DECFRA
+DECGCI
+DECGCR
+DECGNL
+DECGRA
+DECGRI
 DECIC
 DECID
 DECINVM
@@ -430,6 +438,7 @@
 DECSCNM
 DECSCPP
 DECSCUSR
+DECSDM
 DECSED
 DECSEL
 DECSERA
@@ -783,7 +792,7 @@
 Hostx
 HPA
 hpcon
 HPCON
 hpen
 HPR
 HProvider
@@ -1502,6 +1511,7 @@
 rfid
 rftp
 rgbi
+RGBQUAD
 rgbs
 rgci
 rgfae
@@ -1665,9 +1675,11 @@
 Solutiondir
 somefile
 sourced
+SRCAND
 SRCCODEPAGE
 SRCCOPY
 SRCINVERT
+SRCPAINT
 srcsrv
 SRCSRVTRG
 srctool

src/buffer/out/ImageSlice.cpp

@@ -0,0 +1,239 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "precomp.h"
+
+#include "ImageSlice.hpp"
+#include "Row.hpp"
+#include "textBuffer.hpp"
+
+ImageSlice::ImageSlice(const til::size cellSize) noexcept :
+    _cellSize{ cellSize }
+{
+}
+
+til::size ImageSlice::CellSize() const noexcept
+{
+    return _cellSize;
+}
+
+til::CoordType ImageSlice::ColumnOffset() const noexcept
+{
+    return _columnBegin;
+}
+
+til::CoordType ImageSlice::PixelWidth() const noexcept
+{
+    return _pixelWidth;
+}
+
+std::span<const RGBQUAD> ImageSlice::Pixels() const noexcept
+{
+    return _pixelBuffer;
+}
+
+const RGBQUAD* ImageSlice::Pixels(const til::CoordType columnBegin) const noexcept
+{
+    const auto pixelOffset = (columnBegin - _columnBegin) * _cellSize.width;
+    return &til::at(_pixelBuffer, pixelOffset);
+}
+
+RGBQUAD* ImageSlice::MutablePixels(const til::CoordType columnBegin, const til::CoordType columnEnd)
+{
+    // IF the buffer is empty or isn't large enough for the requested range, we'll need to resize it.
+    if (_pixelBuffer.empty() || columnBegin < _columnBegin || columnEnd > _columnEnd)
+    {
+        const auto oldColumnBegin = _columnBegin;
+        const auto oldPixelWidth = _pixelWidth;
+        const auto existingData = !_pixelBuffer.empty();
+        _columnBegin = existingData ? std::min(_columnBegin, columnBegin) : columnBegin;
+        _columnEnd = existingData ? std::max(_columnEnd, columnEnd) : columnEnd;
+        _pixelWidth = (_columnEnd - _columnBegin) * _cellSize.width;
+        _pixelWidth = (_pixelWidth + 3) & ~3; // Renderer needs this as a multiple of 4
+        const auto bufferSize = _pixelWidth * _cellSize.height;
+        if (existingData)
+        {
+            // If there is existing data in the buffer, we need to copy it
+            // across to the appropriate position in the new buffer.
+            auto newPixelBuffer = std::vector<RGBQUAD>(bufferSize);
+            const auto newPixelOffset = (oldColumnBegin - _columnBegin) * _cellSize.width;
+            auto newIterator = std::next(newPixelBuffer.data(), newPixelOffset);
+            auto oldIterator = _pixelBuffer.data();
+            // Because widths are rounded up to multiples of 4, it's possible
+            // that the old width will extend past the right border of the new
+            // buffer, so the range that we copy must be clamped to fit.
+            const auto newPixelRange = std::min(oldPixelWidth, _pixelWidth - newPixelOffset);
+            for (auto i = 0; i < _cellSize.height; i++)
+            {
+                std::memcpy(newIterator, oldIterator, newPixelRange * sizeof(RGBQUAD));
+                std::advance(oldIterator, oldPixelWidth);
+                std::advance(newIterator, _pixelWidth);
+            }
+            _pixelBuffer = std::move(newPixelBuffer);
+        }
+        else
+        {
+            // Otherwise we just initialize the buffer to the correct size.
+            _pixelBuffer.resize(bufferSize);
+        }
+    }
+    const auto pixelOffset = (columnBegin - _columnBegin) * _cellSize.width;
+    return &til::at(_pixelBuffer, pixelOffset);
+}
+
+void ImageSlice::CopyBlock(const TextBuffer& srcBuffer, const til::rect srcRect, TextBuffer& dstBuffer, const til::rect dstRect)
+{
+    // If the top of the source is less than the top of the destination, we copy
+    // the rows from the bottom upwards, to avoid the possibility of the source
+    // being overwritten if it were to overlap the destination range.
+    if (srcRect.top < dstRect.top)
+    {
+        for (auto y = srcRect.height(); y-- > 0;)
+        {
+            const auto& srcRow = srcBuffer.GetRowByOffset(srcRect.top + y);
+            auto& dstRow = dstBuffer.GetMutableRowByOffset(dstRect.top + y);
+            CopyCells(srcRow, srcRect.left, dstRow, dstRect.left, dstRect.right);
+        }
+    }
+    else
+    {
+        for (auto y = 0; y < srcRect.height(); y++)
+        {
+            const auto& srcRow = srcBuffer.GetRowByOffset(srcRect.top + y);
+            auto& dstRow = dstBuffer.GetMutableRowByOffset(dstRect.top + y);
+            CopyCells(srcRow, srcRect.left, dstRow, dstRect.left, dstRect.right);
+        }
+    }
+}
+
+void ImageSlice::CopyRow(const ROW& srcRow, ROW& dstRow)
+{
+    const auto& srcSlice = srcRow.GetImageSlice();
+    auto& dstSlice = dstRow.GetMutableImageSlice();
+    dstSlice = srcSlice ? std::make_unique<ImageSlice>(*srcSlice) : nullptr;
+}
+
+void ImageSlice::CopyCells(const ROW& srcRow, const til::CoordType srcColumn, ROW& dstRow, const til::CoordType dstColumnBegin, const til::CoordType dstColumnEnd)
+{
+    // If there's no image content in the source row, we're essentially copying
+    // a blank image into the destination, which is the same thing as an erase.
+    // Also if the line renditions are different, there's no meaningful way to
+    // copy the image content, so we also just treat that as an erase.
+    const auto& srcSlice = srcRow.GetImageSlice();
+    if (!srcSlice || srcRow.GetLineRendition() != dstRow.GetLineRendition()) [[likely]]
+    {
+        ImageSlice::EraseCells(dstRow, dstColumnBegin, dstColumnEnd);
+    }
+    else
+    {
+        auto& dstSlice = dstRow.GetMutableImageSlice();
+        if (!dstSlice)
+        {
+            dstSlice = std::make_unique<ImageSlice>(srcSlice->CellSize());
+        }
+        const auto scale = srcRow.GetLineRendition() != LineRendition::SingleWidth ? 1 : 0;
+        if (dstSlice->_copyCells(*srcSlice, srcColumn << scale, dstColumnBegin << scale, dstColumnEnd << scale))
+        {
+            // If _copyCells returns true, that means the destination was
+            // completely erased, so we can delete this slice.
+            dstSlice = nullptr;
+        }
+    }
+}
+
+bool ImageSlice::_copyCells(const ImageSlice& srcSlice, const til::CoordType srcColumn, const til::CoordType dstColumnBegin, const til::CoordType dstColumnEnd)
+{
+    const auto srcColumnEnd = srcColumn + dstColumnEnd - dstColumnBegin;
+
+    // First we determine the portions of the copy range that are currently in use.
+    const auto srcUsedBegin = std::max(srcColumn, srcSlice._columnBegin);
+    const auto srcUsedEnd = std::max(std::min(srcColumnEnd, srcSlice._columnEnd), srcUsedBegin);
+    const auto dstUsedBegin = std::max(dstColumnBegin, _columnBegin);
+    const auto dstUsedEnd = std::max(std::min(dstColumnEnd, _columnEnd), dstUsedBegin);
+
+    // The used source projected into the destination is the range we must overwrite.
+    const auto projectedOffset = dstColumnBegin - srcColumn;
+    const auto dstWriteBegin = srcUsedBegin + projectedOffset;
+    const auto dstWriteEnd = srcUsedEnd + projectedOffset;
+
+    if (dstWriteBegin < dstWriteEnd)
+    {
+        auto dstIterator = MutablePixels(dstWriteBegin, dstWriteEnd);
+        auto srcIterator = srcSlice.Pixels(srcUsedBegin);
+        const auto writeCellCount = dstWriteEnd - dstWriteBegin;
+        const auto writeByteCount = sizeof(RGBQUAD) * writeCellCount * _cellSize.width;
+        for (auto y = 0; y < _cellSize.height; y++)
+        {
+            std::memmove(dstIterator, srcIterator, writeByteCount);
+            std::advance(srcIterator, srcSlice._pixelWidth);
+            std::advance(dstIterator, _pixelWidth);
+        }
+    }
+
+    // The used destination before and after the written area must be erased.
+    if (dstUsedBegin < dstWriteBegin)
+    {
+        _eraseCells(dstUsedBegin, dstWriteBegin);
+    }
+    if (dstUsedEnd > dstWriteEnd)
+    {
+        _eraseCells(dstWriteEnd, dstUsedEnd);
+    }
+
+    // If the beginning column is now not less than the end, that means the
+    // content has been entirely erased, so we return true to let the caller
+    // know that the slice should be deleted.
+    return _columnBegin >= _columnEnd;
+}
+
+void ImageSlice::EraseBlock(TextBuffer& buffer, const til::rect rect)
+{
+    for (auto y = rect.top; y < rect.bottom; y++)
+    {
+        auto& row = buffer.GetMutableRowByOffset(y);
+        EraseCells(row, rect.left, rect.right);
+    }
+}
+
+void ImageSlice::EraseCells(ROW& row, const til::CoordType columnBegin, const til::CoordType columnEnd)
+{
+    auto& imageSlice = row.GetMutableImageSlice();
+    if (imageSlice) [[unlikely]]
+    {
+        const auto scale = row.GetLineRendition() != LineRendition::SingleWidth ? 1 : 0;
+        if (imageSlice->_eraseCells(columnBegin << scale, columnEnd << scale))
+        {
+            // If _eraseCells returns true, that means the image was
+            // completely erased, so we can delete this slice.
+            imageSlice = nullptr;
+        }
+    }
+}
+
+bool ImageSlice::_eraseCells(const til::CoordType columnBegin, const til::CoordType columnEnd)
+{
+    if (columnBegin <= _columnBegin && columnEnd >= _columnEnd)
+    {
+        // If we're erasing the entire range that's in use, we return true to
+        // indicate that there is now nothing left. We don't bother altering
+        // the buffer because the caller is now expected to delete this slice.
+        return true;
+    }
+    else
+    {
+        const auto eraseBegin = std::max(columnBegin, _columnBegin);
+        const auto eraseEnd = std::min(columnEnd, _columnEnd);
+        if (eraseBegin < eraseEnd)
+        {
+            const auto eraseOffset = (eraseBegin - _columnBegin) * _cellSize.width;
+            const auto eraseLength = (eraseEnd - eraseBegin) * _cellSize.width;
+            auto eraseIterator = std::next(_pixelBuffer.data(), eraseOffset);
+            for (auto y = 0; y < _cellSize.height; y++)
+            {
+                std::memset(eraseIterator, 0, eraseLength * sizeof(RGBQUAD));
+                std::advance(eraseIterator, _pixelWidth);
+            }
+        }
+        return false;
+    }
+}

src/buffer/out/ImageSlice.hpp

@@ -0,0 +1,52 @@
+/*++
+Copyright (c) Microsoft Corporation
+Licensed under the MIT license.
+
+Module Name:
+- ImageSlice.hpp
+
+Abstract:
+- This serves as a structure to represent a slice of an image covering one textbuffer row.
+--*/
+
+#pragma once
+
+#include "til.h"
+#include <span>
+#include <vector>
+
+class ROW;
+class TextBuffer;
+
+class ImageSlice
+{
+public:
+    using Pointer = std::unique_ptr<ImageSlice>;
+
+    ImageSlice(const ImageSlice& rhs) = default;
+    ImageSlice(const til::size cellSize) noexcept;
+
+    til::size CellSize() const noexcept;
+    til::CoordType ColumnOffset() const noexcept;
+    til::CoordType PixelWidth() const noexcept;
+
+    std::span<const RGBQUAD> Pixels() const noexcept;
+    const RGBQUAD* Pixels(const til::CoordType columnBegin) const noexcept;
+    RGBQUAD* MutablePixels(const til::CoordType columnBegin, const til::CoordType columnEnd);
+
+    static void CopyBlock(const TextBuffer& srcBuffer, const til::rect srcRect, TextBuffer& dstBuffer, const til::rect dstRect);
+    static void CopyRow(const ROW& srcRow, ROW& dstRow);
+    static void CopyCells(const ROW& srcRow, const til::CoordType srcColumn, ROW& dstRow, const til::CoordType dstColumnBegin, const til::CoordType dstColumnEnd);
+    static void EraseBlock(TextBuffer& buffer, const til::rect rect);
+    static void EraseCells(ROW& row, const til::CoordType columnBegin, const til::CoordType columnEnd);
+
+private:
+    bool _copyCells(const ImageSlice& srcSlice, const til::CoordType srcColumn, const til::CoordType dstColumnBegin, const til::CoordType dstColumnEnd);
+    bool _eraseCells(const til::CoordType columnBegin, const til::CoordType columnEnd);
+
+    til::size _cellSize;
+    std::vector<RGBQUAD> _pixelBuffer;
+    til::CoordType _columnBegin = 0;
+    til::CoordType _columnEnd = 0;
+    til::CoordType _pixelWidth = 0;
+};

src/buffer/out/Row.cpp

@@ -227,6 +227,7 @@ void ROW::Reset(const TextAttribute& attr) noexcept
     // Constructing and then moving objects into place isn't free.
     // Modifying the existing object is _much_ faster.
     *_attr.runs().unsafe_shrink_to_size(1) = til::rle_pair{ attr, _columnCount };
+    _imageSlice = nullptr;
     _lineRendition = LineRendition::SingleWidth;
     _wrapForced = false;
     _doubleBytePadded = false;
@@ -930,6 +931,16 @@ std::vector<uint16_t> ROW::GetHyperlinks() const
     return ids;
 }
 
+const ImageSlice::Pointer& ROW::GetImageSlice() const noexcept
+{
+    return _imageSlice;
+}
+
+ImageSlice::Pointer& ROW::GetMutableImageSlice() noexcept
+{
+    return _imageSlice;
+}
+
 uint16_t ROW::size() const noexcept
 {
     return _columnCount;