Revert "remove kA1_Config, as it is no longer supported"

This reverts commit 2d72d8b242eac6e9d30228f5b0a407236491c369.

git-svn-id: http://skia.googlecode.com/svn/trunk@12387 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 55 insertions, 1 deletions

diff --git a/src/pdf/SkPDFImage.cpp b/src/pdf/SkPDFImage.cpp
index 81adcc20d6..a99c9fe390 100644
--- a/src/pdf/SkPDFImage.cpp
+++ b/src/pdf/SkPDFImage.cpp
@@ -36,6 +36,7 @@ static size_t get_uncompressed_size(const SkBitmap& bitmap,
             return srcRect.width() * 3 * srcRect.height();
         case SkBitmap::kARGB_8888_Config:
             return srcRect.width() * 3 * srcRect.height();
+        case SkBitmap::kA1_Config:
         case SkBitmap::kA8_Config:
             return 1;
         default:
@@ -165,6 +166,48 @@ static SkStream* extract_argb8888_data(const SkBitmap& bitmap,
     return stream;
 }
 
+static SkStream* extract_a1_alpha(const SkBitmap& bitmap,
+                                  const SkIRect& srcRect,
+                                  bool* isOpaque,
+                                  bool* isTransparent) {
+    const int alphaRowBytes = (srcRect.width() + 7) / 8;
+    SkStream* stream = SkNEW_ARGS(SkMemoryStream,
+                                  (alphaRowBytes * srcRect.height()));
+    uint8_t* alphaDst = (uint8_t*)stream->getMemoryBase();
+
+    int offset1 = srcRect.fLeft % 8;
+    int offset2 = 8 - offset1;
+
+    for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
+        uint8_t* src = bitmap.getAddr1(0, y);
+        // This may read up to one byte after src, but the
+        // potentially invalid bits are never used for computation.
+        for (int x = srcRect.fLeft; x < srcRect.fRight; x += 8)  {
+            if (offset1) {
+                alphaDst[0] = src[x / 8] << offset1 |
+                    src[x / 8 + 1] >> offset2;
+            } else {
+                alphaDst[0] = src[x / 8];
+            }
+            if (x + 7 < srcRect.fRight) {
+                *isOpaque &= alphaDst[0] == SK_AlphaOPAQUE;
+                *isTransparent &= alphaDst[0] == SK_AlphaTRANSPARENT;
+            }
+            alphaDst++;
+        }
+        // Calculate the mask of bits we're interested in within the
+        // last byte of alphaDst.
+        // width mod 8  == 1 -> 0x80 ... width mod 8 == 7 -> 0xFE
+        uint8_t mask = ~((1 << (8 - (srcRect.width() % 8))) - 1);
+        if (srcRect.width() % 8) {
+            *isOpaque &= (alphaDst[-1] & mask) == (SK_AlphaOPAQUE & mask);
+            *isTransparent &=
+                    (alphaDst[-1] & mask) == (SK_AlphaTRANSPARENT & mask);
+        }
+    }
+    return stream;
+}
+
 static SkStream* extract_a8_alpha(const SkBitmap& bitmap,
                                   const SkIRect& srcRect,
                                   bool* isOpaque,
@@ -240,6 +283,14 @@ static SkStream* extract_image_data(const SkBitmap& bitmap,
             stream = extract_argb8888_data(bitmap, srcRect, extractAlpha,
                                            &isOpaque, &transparent);
             break;
+        case SkBitmap::kA1_Config:
+            if (!extractAlpha) {
+                stream = create_black_image();
+            } else {
+                stream = extract_a1_alpha(bitmap, srcRect,
+                                          &isOpaque, &transparent);
+            }
+            break;
         case SkBitmap::kA8_Config:
             if (!extractAlpha) {
                 stream = create_black_image();
@@ -523,7 +574,8 @@ SkPDFImage::SkPDFImage(SkStream* stream,
     insertName("Type", "XObject");
     insertName("Subtype", "Image");
 
-    bool alphaOnly = (config == SkBitmap::kA8_Config);
+    bool alphaOnly = (config == SkBitmap::kA1_Config ||
+                      config == SkBitmap::kA8_Config);
 
     if (!isAlpha && alphaOnly) {
         // For alpha only images, we stretch a single pixel of black for
@@ -549,6 +601,8 @@ SkPDFImage::SkPDFImage(SkStream* stream,
     int bitsPerComp = 8;
     if (config == SkBitmap::kARGB_4444_Config) {
         bitsPerComp = 4;
+    } else if (isAlpha && config == SkBitmap::kA1_Config) {
+        bitsPerComp = 1;
     }
     insertInt("BitsPerComponent", bitsPerComp);