Revert "Hide SkEncodedInfo"

This reverts commit c6f7a4ffa9522159efc42f7c948bba5e66bb8844.

Reason for revert: Causing differences in Gold, stemming from the fact that this changes the recommended SkImageInfo for 16 bits-per-component PNG from N32 to F16.
- an F16 bitmap already png-encodes to a 16 bits-per-component PNG, but it does not encode a linear colorspace (possibly a bug?). when we decode this PNG using getInfo(), it fails because it has an F16 color type and non-linear colorspace. (In the encode-srgb-png gm, this results in blank results for F16.) We could correct this on the encoder side, but it seems possible that a 16 bits-per-component PNG could be encoded with a different color space. In that case, we'd want SkCodec to recommend F16/SRGBLinear, but I think we'd want the SkCodec to store the encoded SkColorSpace so that we can Xform between the two. Currently SkCodec only stores one color space, so that will require a refactor.
- When decoding 16-bits-per-component PNGs, we are now decoding them to F16. This shows differences in Gold. The srgb/gpu results now look more like F16. I think this is fine.

Original change's description:
> Hide SkEncodedInfo
> 
> Bug: skia:7353
> Bug: skia:6839
> 
> This contains information that is not necessary for clients to know. The
> Color enum tells the number of components in the input, but this is only
> interesting internally (to the SkSwizzler).
> 
> Similarly, the Alpha enum differs from SkAlphaType in that it has
> kBinary instead of kPremul. This is useful information only internally
> for determining whether the SkColorSpaceXform needs to premultiply.
> 
> The bitsPerComponent is potentially useful for a client; Android (in
> SkAndroidCodec) uses it to determine the SkColorType. Rather than
> exposing bitsPerComponent, use it to make the same decision that Android
> would have made - 16 bits per component means to set the info to F16. Add
> a test that computeOutputColorType behaves as expected.
> 
> Switch conversionSupported to use an SkColorType, which is enough info.
> 
> Replace the SkEncodedInfo::Alpha field on SkCodec::FrameInfo with an
> SkAlphaType.
> 
> SkCodec still needs an SkEncodedInfo, so move its header (which is
> already not SK_API) to include/private.
> 
> Change-Id: Ie2cf11339bf999ebfd4390c0f448f7edd6feabda
> Reviewed-on: https://skia-review.googlesource.com/79260
> Reviewed-by: Mike Reed <reed@google.com>
> Reviewed-by: Mike Klein <mtklein@chromium.org>
> Commit-Queue: Leon Scroggins <scroggo@google.com>

TBR=mtklein@chromium.org,scroggo@google.com,reed@google.com

Change-Id: I0c5dd1461e1b70d1e55349a8e7ee6b029c3f556e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:7353, skia:6839
Reviewed-on: https://skia-review.googlesource.com/80660
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

3 files changed, 208 insertions, 5 deletions

diff --git a/include/codec/SkAndroidCodec.h b/include/codec/SkAndroidCodec.h
index 0d6cc185d9..8dfa8ba5fe 100644
--- a/include/codec/SkAndroidCodec.h
+++ b/include/codec/SkAndroidCodec.h
@@ -43,6 +43,8 @@ public:
 
     virtual ~SkAndroidCodec();
 
+    const SkEncodedInfo& getEncodedInfo() const;
+
     const SkImageInfo& getInfo() const { return fInfo; }
 
     /**
diff --git a/include/codec/SkCodec.h b/include/codec/SkCodec.h
index 6a6a597f1f..d3035a7a71 100644
--- a/include/codec/SkCodec.h
+++ b/include/codec/SkCodec.h
@@ -9,11 +9,11 @@
 #define SkCodec_DEFINED
 
 #include "../private/SkTemplates.h"
-#include "../private/SkEncodedInfo.h"
 #include "SkCodecAnimation.h"
 #include "SkColor.h"
 #include "SkColorSpaceXform.h"
 #include "SkEncodedImageFormat.h"
+#include "SkEncodedInfo.h"
 #include "SkEncodedOrigin.h"
 #include "SkImageInfo.h"
 #include "SkPixmap.h"
@@ -169,6 +169,8 @@ public:
      */
     const SkImageInfo& getInfo() const { return fSrcInfo; }
 
+    const SkEncodedInfo& getEncodedInfo() const { return fEncodedInfo; }
+
     /**
      *  Returns the image orientation stored in the EXIF data.
      *  If there is no EXIF data, or if we cannot read the EXIF data, returns kTopLeft.
@@ -610,7 +612,7 @@ public:
          *  This is conservative; it will still return non-opaque if e.g. a
          *  color index-based frame has a color with alpha but does not use it.
          */
-        SkAlphaType fAlphaType;
+        SkEncodedInfo::Alpha fAlpha;
 
         /**
          *  How this frame should be modified before decoding the next one.
@@ -660,8 +662,6 @@ public:
     }
 
 protected:
-    const SkEncodedInfo& getEncodedInfo() const { return fEncodedInfo; }
-
     using XformFormat = SkColorSpaceXform::ColorFormat;
 
     SkCodec(int width,
@@ -847,7 +847,7 @@ private:
      *
      *  Will be called for the appropriate frame, prior to initializing the colorXform.
      */
-    virtual bool conversionSupported(const SkImageInfo& dst, SkColorType srcColor,
+    virtual bool conversionSupported(const SkImageInfo& dst, SkEncodedInfo::Color srcColor,
                                      bool srcIsOpaque, const SkColorSpace* srcCS) const;
     /**
      *  Return whether these dimensions are supported as a scale.
diff --git a/include/codec/SkEncodedInfo.h b/include/codec/SkEncodedInfo.h
new file mode 100644
index 0000000000..dce88cadc1
--- /dev/null
+++ b/include/codec/SkEncodedInfo.h
@@ -0,0 +1,201 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkEncodedInfo_DEFINED
+#define SkEncodedInfo_DEFINED
+
+#include "SkImageInfo.h"
+
+class SkColorSpace;
+
+struct SkEncodedInfo {
+public:
+
+    enum Alpha {
+        kOpaque_Alpha,
+        kUnpremul_Alpha,
+
+        // Each pixel is either fully opaque or fully transparent.
+        // There is no difference between requesting kPremul or kUnpremul.
+        kBinary_Alpha,
+    };
+
+    /*
+     * We strive to make the number of components per pixel obvious through
+     * our naming conventions.
+     * Ex: kRGB has 3 components.  kRGBA has 4 components.
+     *
+     * This sometimes results in redundant Alpha and Color information.
+     * Ex: kRGB images must also be kOpaque.
+     */
+    enum Color {
+        // PNG, WBMP
+        kGray_Color,
+
+        // PNG
+        kGrayAlpha_Color,
+
+        // PNG, GIF, BMP
+        kPalette_Color,
+
+        // PNG, RAW
+        kRGB_Color,
+        kRGBA_Color,
+
+        // BMP
+        kBGR_Color,
+        kBGRX_Color,
+        kBGRA_Color,
+
+        // JPEG, WEBP
+        kYUV_Color,
+
+        // WEBP
+        kYUVA_Color,
+
+        // JPEG
+        // Photoshop actually writes inverted CMYK data into JPEGs, where zero
+        // represents 100% ink coverage.  For this reason, we treat CMYK JPEGs
+        // as having inverted CMYK.  libjpeg-turbo warns that this may break
+        // other applications, but the CMYK JPEGs we see on the web expect to
+        // be treated as inverted CMYK.
+        kInvertedCMYK_Color,
+        kYCCK_Color,
+    };
+
+    static SkEncodedInfo Make(Color color, Alpha alpha, int bitsPerComponent) {
+        SkASSERT(1 == bitsPerComponent ||
+                 2 == bitsPerComponent ||
+                 4 == bitsPerComponent ||
+                 8 == bitsPerComponent ||
+                 16 == bitsPerComponent);
+
+        switch (color) {
+            case kGray_Color:
+                SkASSERT(kOpaque_Alpha == alpha);
+                break;
+            case kGrayAlpha_Color:
+                SkASSERT(kOpaque_Alpha != alpha);
+                break;
+            case kPalette_Color:
+                SkASSERT(16 != bitsPerComponent);
+                break;
+            case kRGB_Color:
+            case kBGR_Color:
+            case kBGRX_Color:
+                SkASSERT(kOpaque_Alpha == alpha);
+                SkASSERT(bitsPerComponent >= 8);
+                break;
+            case kYUV_Color:
+            case kInvertedCMYK_Color:
+            case kYCCK_Color:
+                SkASSERT(kOpaque_Alpha == alpha);
+                SkASSERT(8 == bitsPerComponent);
+                break;
+            case kRGBA_Color:
+                SkASSERT(kOpaque_Alpha != alpha);
+                SkASSERT(bitsPerComponent >= 8);
+                break;
+            case kBGRA_Color:
+            case kYUVA_Color:
+                SkASSERT(kOpaque_Alpha != alpha);
+                SkASSERT(8 == bitsPerComponent);
+                break;
+            default:
+                SkASSERT(false);
+                break;
+        }
+
+        return SkEncodedInfo(color, alpha, bitsPerComponent);
+    }
+
+    /*
+     * Returns an SkImageInfo with Skia color and alpha types that are the
+     * closest possible match to the encoded info.
+     */
+    SkImageInfo makeImageInfo(int width, int height, sk_sp<SkColorSpace> colorSpace) const {
+        switch (fColor) {
+            case kGray_Color:
+                SkASSERT(kOpaque_Alpha == fAlpha);
+                return SkImageInfo::Make(width, height, kGray_8_SkColorType,
+                                         kOpaque_SkAlphaType, colorSpace);
+            case kGrayAlpha_Color:
+                SkASSERT(kOpaque_Alpha != fAlpha);
+                return SkImageInfo::Make(width, height, kN32_SkColorType,
+                        kUnpremul_SkAlphaType, colorSpace);
+            case kPalette_Color: {
+                SkAlphaType alphaType = (kOpaque_Alpha == fAlpha) ? kOpaque_SkAlphaType :
+                        kUnpremul_SkAlphaType;
+                return SkImageInfo::Make(width, height, kN32_SkColorType,
+                                         alphaType, colorSpace);
+            }
+            case kRGB_Color:
+            case kBGR_Color:
+            case kBGRX_Color:
+            case kYUV_Color:
+            case kInvertedCMYK_Color:
+            case kYCCK_Color:
+                SkASSERT(kOpaque_Alpha == fAlpha);
+                return SkImageInfo::Make(width, height, kN32_SkColorType,
+                                         kOpaque_SkAlphaType, colorSpace);
+            case kRGBA_Color:
+            case kBGRA_Color:
+            case kYUVA_Color:
+                SkASSERT(kOpaque_Alpha != fAlpha);
+                return SkImageInfo::Make(width, height, kN32_SkColorType,
+                                         kUnpremul_SkAlphaType, std::move(colorSpace));
+            default:
+                SkASSERT(false);
+                return SkImageInfo::MakeUnknown();
+        }
+    }
+
+    Color color() const { return fColor; }
+    Alpha alpha() const { return fAlpha; }
+    bool opaque() const { return fAlpha == kOpaque_Alpha; }
+
+    uint8_t bitsPerComponent() const { return fBitsPerComponent; }
+
+    uint8_t bitsPerPixel() const {
+        switch (fColor) {
+            case kGray_Color:
+                return fBitsPerComponent;
+            case kGrayAlpha_Color:
+                return 2 * fBitsPerComponent;
+            case kPalette_Color:
+                return fBitsPerComponent;
+            case kRGB_Color:
+            case kBGR_Color:
+            case kYUV_Color:
+                return 3 * fBitsPerComponent;
+            case kRGBA_Color:
+            case kBGRA_Color:
+            case kBGRX_Color:
+            case kYUVA_Color:
+            case kInvertedCMYK_Color:
+            case kYCCK_Color:
+                return 4 * fBitsPerComponent;
+            default:
+                SkASSERT(false);
+                return 0;
+        }
+    }
+
+private:
+
+    SkEncodedInfo(Color color, Alpha alpha, uint8_t bitsPerComponent)
+        : fColor(color)
+        , fAlpha(alpha)
+        , fBitsPerComponent(bitsPerComponent)
+    {}
+
+    Color   fColor;
+    Alpha   fAlpha;
+    uint8_t fBitsPerComponent;
+};
+
+#endif