Switch SkJpegCode to libjpeg-turbo

src/codec/SkJpegCodec.cpp

Index: src/codec/SkJpegCodec.cpp
diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index c12587424ae8a72f919222f3f7e54580d1fa7a52..40b5b179e5327dc28831c44dbc68391dc524de33 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -15,53 +15,22 @@
 #include "SkTemplates.h"
 #include "SkTypes.h"
 
-// stdio is needed for jpeglib
+// stdio is needed for libjpeg-turbo
 #include <stdio.h>
 
 extern "C" {
     #include "jerror.h"
-    #include "jmorecfg.h"
     #include "jpegint.h"
     #include "jpeglib.h"
 }
 
-// ANDROID_RGB
-// If this is defined in the jpeg headers it indicates that jpeg offers
-// support for two additional formats: JCS_RGBA_8888 and JCS_RGB_565.
-
-/*
- * Get the source configuarion for the swizzler
- */
-SkSwizzler::SrcConfig get_src_config(const jpeg_decompress_struct& dinfo) {
-    if (JCS_CMYK == dinfo.out_color_space) {
-        // We will need to perform a manual conversion
-        return  SkSwizzler::kRGBX;
-    }
-    if (3 == dinfo.out_color_components && JCS_RGB == dinfo.out_color_space) {
-        return SkSwizzler::kRGB;
-    }
-#ifdef ANDROID_RGB
-    if (JCS_RGBA_8888 == dinfo.out_color_space) {
-        return SkSwizzler::kRGBX;
-    }
-
-    if (JCS_RGB_565 == dinfo.out_color_space) {
-        return SkSwizzler::kRGB_565;
-    }
-#endif
-    if (1 == dinfo.out_color_components && JCS_GRAYSCALE == dinfo.out_color_space) {
-        return SkSwizzler::kGray;
-    }
-    return SkSwizzler::kUnknown;
-}
-
 /*
  * Convert a row of CMYK samples to RGBX in place.
  * Note that this method moves the row pointer.
  * @param width the number of pixels in the row that is being converted
  *              CMYK is stored as four bytes per pixel
  */
-static void convert_CMYK_to_RGB(uint8_t* row, uint32_t width) {
+static void convert_CMYK_to_RGBA(uint8_t* row, uint32_t width) {

[scroggo, 2015/06/16 20:39:22]

The comment says RGBX. I think X implies A isn't there or it's ignored, whereas
here it's there but always 0xFF. I'm fine with either one, but prefer
consistency.

[msarett, 2015/06/18 21:06:10]

Done.

     // We will implement a crude conversion from CMYK -> RGB using formulas
     // from easyrgb.com.
     //
@@ -168,8 +137,6 @@ SkJpegCodec::SkJpegCodec(const SkImageInfo& srcInfo, SkStream* stream,
         JpegDecoderMgr* decoderMgr)
     : INHERITED(srcInfo, stream)
     , fDecoderMgr(decoderMgr)
-    , fSwizzler(NULL)
-    , fSrcRowBytes(0)
 {}
 
 /*
@@ -177,15 +144,40 @@ SkJpegCodec::SkJpegCodec(const SkImageInfo& srcInfo, SkStream* stream,
  */
 SkISize SkJpegCodec::onGetScaledDimensions(float desiredScale) const {
     // libjpeg supports scaling by 1/1, 1/2, 1/4, and 1/8, so we will support these as well

[scroggo, 2015/06/16 20:39:22]

Update this comment?

[msarett, 2015/06/18 21:06:10]

Done.

-    long scale;
-    if (desiredScale > 0.75f) {
-        scale = 1;
+    long num;
+    long denom = 8;
+    if (desiredScale > 1.875f) {

[scroggo, 2015/06/16 20:39:22]

Wait, libjpeg scales up? What is the advantage to that?

[msarett, 2015/06/18 21:06:10]

Oops, I added this for testing jpeg_skip_scanlines().  As we've discussed, we
don't intend to support upscaling.

+        num = 16;
+    } else if (desiredScale > 1.75f) {
+        num = 15;
+    } else if (desiredScale > 1.625f) {
+        num = 14;
+    } else if (desiredScale > 1.5f) {
+        num = 13;
+    } else if (desiredScale > 1.375f) {
+        num = 12;
+    } else if (desiredScale > 1.25f) {
+        num = 11;
+    } else if (desiredScale > 1.125f) {
+        num = 10;
+    } else if (desiredScale > 1.0f) {
+        num = 9;
+    } else if (desiredScale > 0.875f) {
+        num = 8;
+    } else if (desiredScale > 0.75f) {
+        num = 7;
+    } else if (desiredScale > 0.625f) {
+        num = 6;
+    } else if (desiredScale > 0.5f) {
+        num = 5;
     } else if (desiredScale > 0.375f) {
-        scale = 2;
-    } else if (desiredScale > 0.1875f) {
-        scale = 4;
+        num = 4;
+    } else if (desiredScale > 0.25f) {
+        num = 3;
+    } else if (desiredScale > 0.125f) {
+        num = 2;
     } else {
-        scale = 8;
+        num = 1;
     }
 
     // Set up a fake decompress struct in order to use libjpeg to calculate output dimensions
@@ -195,8 +187,8 @@ SkISize SkJpegCodec::onGetScaledDimensions(float desiredScale) const {
     dinfo.image_height = this->getInfo().height();
     dinfo.global_state = DSTATE_READY;
     dinfo.num_components = 0;
-    dinfo.scale_num = 1;
-    dinfo.scale_denom = scale;
+    dinfo.scale_num = num;
+    dinfo.scale_denom = denom;
     jpeg_calc_output_dimensions(&dinfo);
 
     // Return the calculated output dimensions for the given scale
@@ -204,31 +196,6 @@ SkISize SkJpegCodec::onGetScaledDimensions(float desiredScale) const {
 }
 
 /*
- * Checks if the conversion between the input image and the requested output
- * image has been implemented
- */
-static bool conversion_possible(const SkImageInfo& dst,
-                                const SkImageInfo& src) {
-    // Ensure that the profile type is unchanged
-    if (dst.profileType() != src.profileType()) {
-        return false;
-    }
-
-    // Ensure that the alpha type is opaque
-    if (kOpaque_SkAlphaType != dst.alphaType()) {
-        return false;
-    }
-
-    // Always allow kN32 as the color type
-    if (kN32_SkColorType == dst.colorType()) {
-        return true;
-    }
-
-    // Otherwise require that the destination color type match our recommendation
-    return dst.colorType() == src.colorType();
-}
-
-/*
  * Handles rewinding the input stream if it is necessary
  */
 bool SkJpegCodec::handleRewind() {
@@ -253,6 +220,60 @@ bool SkJpegCodec::handleRewind() {
 }
 
 /*
+ * Checks if the conversion between the input image and the requested output
+ * image has been implemented
+ * Sets the output color space
+ */
+bool SkJpegCodec::setOutputColorSpace(const SkImageInfo& dst) {
+    const SkImageInfo& src = this->getInfo();
+
+    // Ensure that the profile type is unchanged
+    if (dst.profileType() != src.profileType()) {
+        return false;
+    }
+
+    // Ensure that the alpha type is opaque
+    if (kOpaque_SkAlphaType != dst.alphaType()) {
+        return false;
+    }
+
+    // Check if we will decode to CMYK because a conversion to RGBA is not supported
+    bool isCMYK = JCS_CMYK == fDecoderMgr->dinfo()->jpeg_color_space ||

[scroggo, 2015/06/16 20:39:22]

nit: I find this more readable if you use a temporary variable:

auto jpeg_color_space = fDecoderMgr->dinfo()->jpeg_color_space;
bool isCMYK = JCS_CMYK == jpeg_color_space || JCS_YCCK == jpeg_color_space;

[msarett, 2015/06/18 21:06:10]

Done.

+            JCS_YCCK == fDecoderMgr->dinfo()->jpeg_color_space;
+
+    // Check for valid color types and set the output color space
+    switch (dst.colorType()) {
+        case kN32_SkColorType:
+            if (isCMYK) {
+                fDecoderMgr->dinfo()->out_color_space = JCS_CMYK;
+            } else {
+                fDecoderMgr->dinfo()->out_color_space = JCS_EXT_RGBA;
+            }
+            return true;
+        case kRGB_565_SkColorType:
+            if (isCMYK) {
+                return false;
+            } else {
+                //fDecoderMgr->dinfo()->out_color_space = JCS_EXT_RGBA;
+                // TODO (msarett):

[scroggo, 2015/06/16 20:39:22]

What is the TODO here?

[msarett, 2015/06/18 21:06:10]

This has been done!  The original issue was caused by the fact that turbo and
patched libjpeg have different names for RGB565.

+                fDecoderMgr->dinfo()->out_color_space = JCS_RGB565;
+            }
+            return true;
+        case kGray_8_SkColorType:
+            if (isCMYK) {
+                return false;
+            } else {
+                // We will enable decodes to gray even if the image is color because this is

[scroggo, 2015/06/16 20:39:22]

Does libjpeg(-turbo) support converting full color to grayscale? Oh, I guess due
to the way jpeg is stored this is easy for them to provide? I don't know that
anyone wants this, but if it's easy to support I'm not opposed to it.

[msarett, 2015/06/18 21:06:10]

I have no recollection of writing this comment, and I'm not sure what made me
put this code here haha.  Having said that, I just tested and this works.  As
you said, I guess I don't see a reason to unsupport this.

+                // much faster than decoding to color and then converting
+                fDecoderMgr->dinfo()->out_color_space = JCS_GRAYSCALE;
+            }
+            return true;
+        default:
+            return false;
+    }
+}
+
+/*
  * Checks if we can scale to the requested dimensions and scales the dimensions
  * if possible
  */
@@ -260,37 +281,26 @@ bool SkJpegCodec::scaleToDimensions(uint32_t dstWidth, uint32_t dstHeight) {
     // libjpeg can scale to 1/1, 1/2, 1/4, and 1/8
     SkASSERT(1 == fDecoderMgr->dinfo()->scale_num);
     SkASSERT(1 == fDecoderMgr->dinfo()->scale_denom);
+    fDecoderMgr->dinfo()->scale_denom = 8;
     jpeg_calc_output_dimensions(fDecoderMgr->dinfo());
     while (fDecoderMgr->dinfo()->output_width != dstWidth ||
             fDecoderMgr->dinfo()->output_height != dstHeight) {
 
         // Return a failure if we have tried all of the possible scales
-        if (8 == fDecoderMgr->dinfo()->scale_denom ||
-                dstWidth > fDecoderMgr->dinfo()->output_width ||
-                dstHeight > fDecoderMgr->dinfo()->output_height) {
+        if (16 == fDecoderMgr->dinfo()->scale_num ||
+                dstWidth < fDecoderMgr->dinfo()->output_width ||
+                dstHeight < fDecoderMgr->dinfo()->output_height) {
             return fDecoderMgr->returnFalse("could not scale to requested dimensions");
         }
 
         // Try the next scale
-        fDecoderMgr->dinfo()->scale_denom *= 2;
+        fDecoderMgr->dinfo()->scale_num += 1;
         jpeg_calc_output_dimensions(fDecoderMgr->dinfo());
     }
     return true;
 }
 
 /*
- * Create the swizzler based on the encoded format
- */
-void SkJpegCodec::initializeSwizzler(const SkImageInfo& dstInfo,
-                                     void* dst, size_t dstRowBytes,
-                                     const Options& options) {
-    SkSwizzler::SrcConfig srcConfig = get_src_config(*fDecoderMgr->dinfo());
-    fSwizzler.reset(SkSwizzler::CreateSwizzler(srcConfig, NULL, dstInfo, dst, dstRowBytes,
-            options.fZeroInitialized));
-    fSrcRowBytes = SkSwizzler::BytesPerPixel(srcConfig) * dstInfo.width();
-}
-
-/*
  * Performs the jpeg decode
  */
 SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
@@ -310,13 +320,14 @@ SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
         return fDecoderMgr->returnFailure("setjmp", kInvalidInput);
     }
 
-    // Check if we can decode to the requested destination
-    if (!conversion_possible(dstInfo, this->getInfo())) {
+    // Check if we can decode to the requested destination and set the output color space
+    if (!this->setOutputColorSpace(dstInfo)) {
         return fDecoderMgr->returnFailure("conversion_possible", kInvalidConversion);
     }
 
     // Perform the necessary scaling
     if (!this->scaleToDimensions(dstInfo.width(), dstInfo.height())) {
+        SkDebugf("POOPY\n");

[scroggo, 2015/06/16 20:39:22]

lol

[msarett, 2015/06/18 21:06:10]

Probably not necessary...

         fDecoderMgr->returnFailure("cannot scale to requested dims", kInvalidScale);

[scroggo, 2015/06/16 20:39:22]

Should this say *return* fDecoderMgr->returnFailure(...)?

[msarett, 2015/06/18 21:06:10]

Yes!

     }
 
@@ -325,54 +336,25 @@ SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
         return fDecoderMgr->returnFailure("startDecompress", kInvalidInput);
     }
 
-    // Create the swizzler
-    this->initializeSwizzler(dstInfo, dst, dstRowBytes, options);
-    if (NULL == fSwizzler) {
-        return fDecoderMgr->returnFailure("getSwizzler", kUnimplemented);
-    }
-
-    // This is usually 1, but can also be 2 or 4.
-    // If we wanted to always read one row at a time, we could, but we will save space and time
-    // by using the recommendation from libjpeg.
-    const uint32_t rowsPerDecode = dinfo->rec_outbuf_height;
-    SkASSERT(rowsPerDecode <= 4);
-
-    // Create a buffer to contain decoded rows (libjpeg requires a 2D array)
-    SkASSERT(0 != fSrcRowBytes);
-    SkAutoTDeleteArray<uint8_t> srcBuffer(SkNEW_ARRAY(uint8_t, fSrcRowBytes * rowsPerDecode));
-    JSAMPLE* srcRows[4];
-    uint8_t* srcPtr = srcBuffer.get();
-    for (uint8_t i = 0; i < rowsPerDecode; i++) {
-        srcRows[i] = (JSAMPLE*) srcPtr;
-        srcPtr += fSrcRowBytes;
-    }
+    // The recommended output buffer height should always be 1 in high quality modes
+    SkDEBUGCODE(const uint32_t rowsPerDecode = dinfo->rec_outbuf_height;)

[scroggo, 2015/06/16 20:39:22]

This variable is never used after the assert. How about:

SkASSERT(1 == dinfo->rec_outbuf_height);

[msarett, 2015/06/18 21:06:10]

Done.

+    SkASSERT(1 == rowsPerDecode);
 
-    // Ensure that we loop enough times to decode all of the rows
-    // libjpeg will prevent us from reading past the bottom of the image
+    // Perform the decode a single row at a time
     uint32_t dstHeight = dstInfo.height();
-    for (uint32_t y = 0; y < dstHeight + rowsPerDecode - 1; y += rowsPerDecode) {
+    JSAMPLE* dstRow = (JSAMPLE*) dst;
+    for (uint32_t y = 0; y < dstHeight; y++) {
         // Read rows of the image
-        uint32_t rowsDecoded = jpeg_read_scanlines(dinfo, srcRows, rowsPerDecode);
-
-        // Convert to RGB if necessary
-        if (JCS_CMYK == dinfo->out_color_space) {
-            convert_CMYK_to_RGB(srcRows[0], dstInfo.width() * rowsDecoded);
-        }
-
-        // Swizzle to output destination
-        for (uint32_t i = 0; i < rowsDecoded; i++) {
-            fSwizzler->next(srcRows[i]);
-        }
+        uint32_t rowsDecoded = jpeg_read_scanlines(dinfo, &dstRow, 1);
 
         // If we cannot read enough rows, assume the input is incomplete
-        if (rowsDecoded < rowsPerDecode && y + rowsDecoded < dstHeight) {
+        if (rowsDecoded != 1) {
             // Fill the remainder of the image with black. This error handling
             // behavior is unspecified but SkCodec consistently uses black as
             // the fill color for opaque images.  If the destination is kGray,
             // the low 8 bits of SK_ColorBLACK will be used.  Conveniently,
             // these are zeros, which is the representation for black in kGray.
-            SkSwizzler::Fill(fSwizzler->getDstRow(), dstInfo, dstRowBytes,
-                    dstHeight - y - rowsDecoded, SK_ColorBLACK, NULL);
+            SkSwizzler::Fill(dstRow, dstInfo, dstRowBytes, dstHeight - y, SK_ColorBLACK, NULL);
 
             // Prevent libjpeg from failing on incomplete decode
             dinfo->output_scanline = dstHeight;
@@ -381,6 +363,14 @@ SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
             jpeg_finish_decompress(dinfo);
             return fDecoderMgr->returnFailure("Incomplete image data", kIncompleteInput);
         }
+
+        // Convert to RGBA if necessary
+        if (JCS_CMYK == dinfo->out_color_space) {
+            convert_CMYK_to_RGBA(dstRow, dstInfo.width());
+        }
+
+        // Move to the next row
+        dstRow = SkTAddOffset<JSAMPLE>(dstRow, dstRowBytes);
     }
     jpeg_finish_decompress(dinfo);
 
@@ -396,8 +386,6 @@ public:
         : INHERITED(dstInfo)
         , fCodec(codec)
     {
-        fStorage.reset(fCodec->fSrcRowBytes);
-        fSrcRow = static_cast<uint8_t*>(fStorage.get());
     }
 
     SkImageGenerator::Result onGetScanlines(void* dst, int count, size_t rowBytes) override {
@@ -407,23 +395,23 @@ public:
         }
 
         // Read rows one at a time
+        JSAMPLE* dstRow = (JSAMPLE*) dst;
         for (int y = 0; y < count; y++) {
             // Read row of the image
-            uint32_t rowsDecoded = jpeg_read_scanlines(fCodec->fDecoderMgr->dinfo(), &fSrcRow, 1);
+            uint32_t rowsDecoded = jpeg_read_scanlines(fCodec->fDecoderMgr->dinfo(), &dstRow, 1);

[scroggo, 2015/06/16 20:39:23]

Wait, we don't need to do any conversion? (besides from CMYK) Does JCS_EXT_RGBA
output to SkPMColor? Do we need to make sure libjpeg-turbo is compiled with the
same color ordering as Skia?

[msarett, 2015/06/18 21:06:10]

Yes we do.  As it happens, this works on Android but was broken for my desktop. 
I have fixed this in setOutputColorSpace.

             if (rowsDecoded != 1) {
-                SkSwizzler::Fill(dst, this->dstInfo(), rowBytes, count - y, SK_ColorBLACK, NULL);
+                SkSwizzler::Fill(dstRow, this->dstInfo(), rowBytes, count - y, SK_ColorBLACK, NULL);
+                fCodec->fDecoderMgr->dinfo()->output_scanline = this->dstInfo().height();

[scroggo, 2015/06/16 20:39:22]

Do we need to call jpeg_finish_decompress? (whether we got the error case or
not)

[msarett, 2015/06/18 21:06:10]

Yes we should call this!  I think I wrongly assumed onFinish() would be called,
but it won't if we never reach the end of the image.

                 return SkImageGenerator::kIncompleteInput;
             }
 
-            // Convert to RGB if necessary
+            // Convert to RGBA if necessary
             if (JCS_CMYK == fCodec->fDecoderMgr->dinfo()->out_color_space) {
-                convert_CMYK_to_RGB(fSrcRow, dstInfo().width());
+                convert_CMYK_to_RGBA(dstRow, this->dstInfo().width());
             }
 
-            // Swizzle to output destination
-            fCodec->fSwizzler->setDstRow(dst);
-            fCodec->fSwizzler->next(fSrcRow);
-            dst = SkTAddOffset<void>(dst, rowBytes);
+            // Move to the next row
+            dstRow = SkTAddOffset<JSAMPLE>(dstRow, rowBytes);
         }
 
         return SkImageGenerator::kSuccess;
@@ -435,10 +423,7 @@ public:
             return fCodec->fDecoderMgr->returnFailure("setjmp", SkImageGenerator::kInvalidInput);
         }
 
-        // Read rows but ignore the output
-        for (int y = 0; y < count; y++) {
-            jpeg_read_scanlines(fCodec->fDecoderMgr->dinfo(), &fSrcRow, 1);
-        }
+        jpeg_skip_scanlines(fCodec->fDecoderMgr->dinfo(), count);
 
         return SkImageGenerator::kSuccess;
     }
@@ -454,8 +439,6 @@ public:
 
 private:
     SkJpegCodec*        fCodec;     // unowned
-    SkAutoMalloc        fStorage;
-    uint8_t*            fSrcRow;    // ptr into fStorage
 
     typedef SkScanlineDecoder INHERITED;
 };
@@ -475,15 +458,15 @@ SkScanlineDecoder* SkJpegCodec::onGetScanlineDecoder(const SkImageInfo& dstInfo,
         return NULL;
     }
 
-    // Check if we can decode to the requested destination
-    if (!conversion_possible(dstInfo, this->getInfo())) {
+    // Check if we can decode to the requested destination and set the output color space
+    if (!this->setOutputColorSpace(dstInfo)) {
         SkCodecPrintf("Cannot convert to output type\n");
         return NULL;
     }
 
     // Perform the necessary scaling
     if (!this->scaleToDimensions(dstInfo.width(), dstInfo.height())) {
-        SkCodecPrintf("Cannot scale ot output dimensions\n");
+        SkCodecPrintf("Cannot scale to output dimensions\n");
         return NULL;
     }
 
@@ -493,13 +476,6 @@ SkScanlineDecoder* SkJpegCodec::onGetScanlineDecoder(const SkImageInfo& dstInfo,
         return NULL;
     }
 
-    // Create the swizzler
-    this->initializeSwizzler(dstInfo, NULL, dstInfo.minRowBytes(), options);
-    if (NULL == fSwizzler) {
-        SkCodecPrintf("Could not create swizzler\n");
-        return NULL;
-    }
-
     // Return the new scanline decoder
     return SkNEW_ARGS(SkJpegScanlineDecoder, (dstInfo, this));
 }