docs/SkImageInfo_Reference.bmh

#Topic Image_Info
#Alias Image_Info_Reference

Image_Info specifies the dimensions and encoding of the pixels in a Bitmap.
The dimensions are integral width and height. The encoding is how pixel
bits describe Color_Alpha, transparency; Color components red, blue,
and green; and Color_Space, the range and linearity of colors.

Image_Info describes an uncompressed raster pixels. In contrast, Image
additionally describes compressed pixels like PNG, and Surface describes
destinations on the GPU. Image and Surface may be specified by Image_Info,
but Image and Surface may not contain Image_Info.

#Subtopic Overview
    #Subtopic Subtopic
    #Populate
    ##
##

#Subtopic Constant
#Populate
##

# ------------------------------------------------------------------------------
#Subtopic Alpha_Type
#Line # encoding for pixel transparency ##
#Alias Alpha_Type
#Alias Alpha_Types

#Enum SkAlphaType
#Line # encoding for pixel transparency ##

#Code
    enum SkAlphaType {
        kUnknown_SkAlphaType,
        kOpaque_SkAlphaType,
        kPremul_SkAlphaType,
        kUnpremul_SkAlphaType,
        kLastEnum_SkAlphaType = kUnpremul_SkAlphaType,
    };
##

Describes how to interpret the alpha component of a pixel. A pixel may
be opaque, or Color_Alpha, describing multiple levels of transparency.

In simple blending, Color_Alpha weights the draw color and the destination
color to create a new color. If alpha describes a weight from zero to one:

#Formula
    new color = draw color * alpha + destination color * (1 - alpha)
##

In practice alpha is encoded in two or more bits, where 1.0 equals all bits set.

Color_RGB may have Color_Alpha included in each component value; the stored
value is the original Color_RGB multiplied by Color_Alpha. Premultiplied color
components improve performance.

#Const kUnknown_SkAlphaType 0
Alpha_Type is uninitialized.
##
#Const kOpaque_SkAlphaType 1
Pixels are opaque. The Color_Type must have no explicit alpha
component, or all alpha components must be set to their maximum value.
##
#Const kPremul_SkAlphaType 2
Pixels have alpha premultiplied into color components.
Surface pixels must be premultiplied.
##
#Const kUnpremul_SkAlphaType 3
Pixel color component values are independent of alpha value.
Images generated from encoded data like PNG do not premultiply pixel color
components. kUnpremul_SkAlphaType is supported for Image pixels, but not for
Surface pixels.
##

#NoExample
##

#SeeAlso SkColorType SkColorSpace

#Enum SkAlphaType ##

#Subtopic Opaque

Use Opaque as a hint to optimize drawing when alpha component
of all pixel is set to its maximum value of 1.0; all alpha component bits are set.
If Image_Info is set to Opaque but all alpha values are not 1.0, results are
undefined.

#Example
#Height 64
#Description
SkPreMultiplyARGB parameter a is set to 255, its maximum value, and is interpreted
as Color_Alpha of 1.0. kOpaque_SkAlphaType may be set to improve performance.
If SkPreMultiplyARGB parameter a is set to a value smaller than 255, 
kPremul_SkAlphaType must be used instead to avoid undefined results.
The four displayed values are the original component values, though not necessarily
in the same order.
##
    SkPMColor color = SkPreMultiplyARGB(255, 50, 100, 150);
    SkString s;
    s.printf("%u %u %u %u", SkColorGetA(color), SkColorGetR(color),
                            SkColorGetG(color), SkColorGetB(color));
    SkPaint paint;
    paint.setAntiAlias(true);
    canvas->drawString(s, 10, 62, paint);
    canvas->scale(50, 50);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(1, 1, kN32_SkColorType, kOpaque_SkAlphaType);
    if (bitmap.installPixels(imageInfo, (void*) &color, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 0, 0);
    }
##

#Subtopic Opaque ##

#Subtopic Premul

Use Premul when stored color components are the original color multiplied by the
alpha component. The alpha component range of 0.0 to 1.0 is achieved by dividing
the integer bit value by the maximum bit value.

#Formula
stored color = original color * alpha / max alpha
##

The color component must be equal to or smaller than the alpha component,
or the results are undefined.

#Example
#Description
SkPreMultiplyARGB parameter a is set to 150, less than its maximum value, and is
interpreted as Color_Alpha of about 0.6. kPremul_SkAlphaType must be set, since
SkPreMultiplyARGB parameter a is set to a value smaller than 255, 
to avoid undefined results.
The four displayed values reflect that the alpha component has been multiplied
by the original color.
##
#Height 64
    SkPMColor color = SkPreMultiplyARGB(150, 50, 100, 150);
    SkString s;
    s.printf("%u %u %u %u", SkColorGetA(color), SkColorGetR(color),
                            SkColorGetG(color), SkColorGetB(color));
    SkPaint paint;
    paint.setAntiAlias(true);
    canvas->drawString(s, 10, 62, paint);
    canvas->scale(50, 50);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(1, 1, kN32_SkColorType, kPremul_SkAlphaType);
    if (bitmap.installPixels(imageInfo, (void*) &color, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 0, 0);
    }
##

#Subtopic Premul ##

#Subtopic Unpremul

Use Unpremul if stored color components are not divided by the alpha component.
Some drawing destinations may not support Unpremul.

#Bug 7079
#Example
#Description
SkColorSetARGB parameter a is set to 150, less than its maximum value, and is
interpreted as Color_Alpha of about 0.6. color is not premultiplied;
color components may have values greater than color alpha.
The four displayed values are the original component values, though not necessarily
in the same order.
##
    SkColor color = SkColorSetARGB(150, 50, 100, 255);
    SkString s;
    s.printf("%u %u %u %u", SkColorGetA(color), SkColorGetR(color),
                            SkColorGetG(color), SkColorGetB(color));
    SkPaint paint;
    paint.setAntiAlias(true);
    canvas->drawString(s, 10, 62, paint);
    canvas->scale(50, 50);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(1, 1, kN32_SkColorType, kUnpremul_SkAlphaType);
    if (bitmap.installPixels(imageInfo, (void*) &color, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 0, 0);
    }
##

#Subtopic Unpremul ##

#Subtopic Alpha_Type ##

# ------------------------------------------------------------------------------
#Subtopic Color_Type
#Line # encoding for pixel color ##
#Alias Color_Type
#Alias Color_Types

#Subtopic Native
#Alias Native_Color_Type
#Substitute native SkColorType
##

#Enum SkColorType
#Line # encoding for pixel color ##

#Code
    enum SkColorType {
        kUnknown_SkColorType,
        kAlpha_8_SkColorType,
        kRGB_565_SkColorType,
        kARGB_4444_SkColorType,
        kRGBA_8888_SkColorType,
        kRGB_888x_SkColorType,
        kBGRA_8888_SkColorType,
        kRGBA_1010102_SkColorType,
        kRGB_101010x_SkColorType,
        kGray_8_SkColorType,
        kRGBA_F16_SkColorType,
        kLastEnum_SkColorType = kRGBA_F16_SkColorType,
        kN32_SkColorType = kBGRA_8888_SkColorType,
        kN32_SkColorType = kRGBA_8888_SkColorType,
    };
##

Describes how pixel bits encode color. A pixel may be an alpha mask, a
gray level, Color_RGB, or Color_ARGB. 

kN32_SkColorType selects the native 32-bit Color_ARGB format. On Little_Endian
processors, pixels containing 8-bit Color_ARGB components pack into 32-bit
kBGRA_8888_SkColorType. On Big_Endian processors, pixels pack into 32-bit
kRGBA_8888_SkColorType.

#Const kUnknown_SkColorType 0

##
#Const kAlpha_8_SkColorType 1
    Encodes Color_Alpha as Alpha_8 pixel in an 8-bit byte.
##
#Const kRGB_565_SkColorType 2
    Encodes Color_RGB as BGR_565 pixel in a 16-bit word.
##
#Const kARGB_4444_SkColorType 3
    Encodes Color_ARGB as ABGR_4444 pixel in a 16-bit word.
##
#Const kRGBA_8888_SkColorType 4
    Encodes Color_ARGB as RGBA_8888 pixel in a 32-bit word.
##
#Const kRGB_888x_SkColorType 5
    Encodes Color_RGB as RGB_888x pixel in a 32-bit word.
##
#Const kBGRA_8888_SkColorType 6
    Encodes Color_ARGB as BGRA_8888 pixel in a 32-bit word.
##
#Const kRGBA_1010102_SkColorType 7
    Encodes Color_ARGB as RGBA_1010102 pixel in a 32-bit word.
##
#Const kRGB_101010x_SkColorType 8
    Encodes Color_RGB as RGB_101010x pixel in a 32-bit word.
##
#Const kGray_8_SkColorType 9
    Encodes Color_Gray as Gray_8 in an 8-bit byte.
##
#Const kRGBA_F16_SkColorType 10
    Encodes Color_ARGB as RGBA_F16 in a 64-bit word.
##

#ToDo  can be 4 or 6; how to document? ##
#Const kN32_SkColorType 4
    Encodes Color_ARGB as either RGBA_8888 or BGRA_8888, whichever
    is native to the platform.
##

#NoExample
##

#SeeAlso SkAlphaType SkColorSpace

#Enum SkColorType ##

#Subtopic Alpha_8

Alpha_8 is an 8-bit byte pixel encoding that represents transparency. A value of zero is
completely transparent; a value of 255 is completely opaque. Bitmap with Alpha_8
pixels does not visibly draw, because its pixels have no color information.
The paired SkAlphaType is ignored.

#Example
#Description
Alpha_8 pixels can modify another draw. orangePaint fills the bounds of bitmap,
with its transparency set to alpha8 pixel value.
##
#Height 64
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kAlpha_8_SkColorType, kOpaque_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    SkPaint orangePaint;
    orangePaint.setARGB(0xFF, 0xFF, 0xA5, 0x00);
    canvas->drawBitmap(bitmap, 0, 0, &orangePaint);
    uint8_t alpha8[] = { 0xFF, 0xBB, 0x77, 0x33 };
    SkPixmap alphaPixmap(imageInfo, &alpha8, imageInfo.minRowBytes());
    if (bitmap.writePixels(alphaPixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 2, 2, &orangePaint);
    }
##
##

#Subtopic BGR_565

BGR_565 is a 16-bit word pixel encoding that contains five bits of blue,
six bits of green, and five bits of red. BGR_565 is fully opaque as if its
Color_Alpha was set to one, and should always be paired with kOpaque_SkAlphaType.

#Illustration

#Example
#Height 96
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGB_565_SkColorType, kOpaque_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto pack565 = [](unsigned r, unsigned g, unsigned b) -> uint16_t {
        return (b << 0) | (g << 5) | (r << 11);
    };
    uint16_t red565[] =  { pack565(0x1F, 0x00, 0x00), pack565(0x17, 0x00, 0x00), 
                           pack565(0x0F, 0x00, 0x00), pack565(0x07, 0x00, 0x00) };
    uint16_t blue565[] = { pack565(0x00, 0x00, 0x1F), pack565(0x00, 0x00, 0x17),
                           pack565(0x00, 0x00, 0x0F), pack565(0x00, 0x00, 0x07) };
    SkPixmap redPixmap(imageInfo, &red565, imageInfo.minRowBytes());
    if (bitmap.writePixels(redPixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    SkPixmap bluePixmap(imageInfo, &blue565, imageInfo.minRowBytes());
    if (bitmap.writePixels(bluePixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
##
##

#Subtopic ABGR_4444

ABGR_4444 is a 16-bit word pixel encoding that contains four bits of alpha,
four bits of blue, four bits of green, and four bits of red. 

#Illustration

If paired with kPremul_SkAlphaType: blue, green, and red components are
premultiplied by the alpha value. If blue, green, or red is greater than alpha,
the drawn result is undefined.

If paired with kUnpremul_SkAlphaType: alpha, blue, green, and red components
may have any value. There may be a performance penalty with unpremultipled
pixels.

If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum;
blue, green, and red components are fully opaque. If any alpha component is
less than 15, the drawn result is undefined.

#Bug 7648

#Example
#Height 96
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kARGB_4444_SkColorType, kPremul_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto pack4444 = [](unsigned a, unsigned r, unsigned g, unsigned b) -> uint16_t {
        return (a << 0) | (b << 4) | (g << 8) | (r << 12);
    };
    uint16_t red4444[] =  { pack4444(0xF, 0xF, 0x0, 0x0), pack4444(0xF, 0xb, 0x0, 0x0), 
                            pack4444(0xF, 0x7, 0x0, 0x0), pack4444(0xF, 0x3, 0x0, 0x0) };
    uint16_t blue4444[] = { pack4444(0xF, 0x0, 0x0, 0xF), pack4444(0xF, 0x0, 0x0, 0xb),
                            pack4444(0xF, 0x0, 0x0, 0x7), pack4444(0xF, 0x0, 0x0, 0x3) };
    SkPixmap redPixmap(imageInfo, &red4444, imageInfo.minRowBytes());
    if (bitmap.writePixels(redPixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    SkPixmap bluePixmap(imageInfo, &blue4444, imageInfo.minRowBytes());
    if (bitmap.writePixels(bluePixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
##
##

#Subtopic RGBA_8888

RGBA_8888 is a 32-bit word pixel encoding that contains eight bits of red,
eight bits of green, eight bits of blue, and eight bits of alpha. 

#Illustration

If paired with kPremul_SkAlphaType: red, green, and blue components are
premultiplied by the alpha value. If red, green, or blue is greater than alpha,
the drawn result is undefined.

If paired with kUnpremul_SkAlphaType: alpha, red, green, and blue components
may have any value. There may be a performance penalty with unpremultipled
pixels.

If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum; 
red, green, and blue components are fully opaque. If any alpha component is
less than 255, the drawn result is undefined.

On Big_Endian platforms, RGBA_8888 is the native Color_Type, and will have
the best performance. Use kN32_SkColorType to choose the best Color_Type for
the platform at compile time.

#Example
#Height 96
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGBA_8888_SkColorType, kPremul_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto pack8888 = [](unsigned a, unsigned r, unsigned g, unsigned b) -> uint32_t {
        return (r << 0) | (g << 8) | (b << 16) | (a << 24);
    };
    uint32_t red8888[] = { pack8888(0xFF, 0xFF, 0x0, 0x0), pack8888(0xFF, 0xbb, 0x0, 0x0), 
                           pack8888(0xFF, 0x77, 0x0, 0x0), pack8888(0xFF, 0x33, 0x0, 0x0) };
    uint32_t blue8888[] = { pack8888(0xFF, 0x0, 0x0, 0x0FF), pack8888(0xFF, 0x0, 0x0, 0x0bb),
                            pack8888(0xFF, 0x0, 0x0, 0x077), pack8888(0xFF, 0x0, 0x0, 0x033) };
    SkPixmap redPixmap(imageInfo, &red8888, imageInfo.minRowBytes());
    if (bitmap.writePixels(redPixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    SkPixmap bluePixmap(imageInfo, &blue8888, imageInfo.minRowBytes());
    if (bitmap.writePixels(bluePixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
##
##

#Subtopic RGB_888x

RGB_888x is a 32-bit word pixel encoding that contains eight bits of red,
eight bits of green, eight bits of blue, and eight unused bits. RGB_888x is fully 
opaque as if its Color_Alpha was set to one, and should always be paired with
kOpaque_SkAlphaType.

#Illustration

#Example
#Bug 7645
#Height 96
#Platform cpu
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGB_888x_SkColorType, kOpaque_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto pack888 = [](unsigned r, unsigned g, unsigned b) -> uint32_t {
        return (r << 0) | (g << 8) | (b << 16);
    };
    uint32_t red888[] =  { pack888(0xFF, 0x00, 0x00), pack888(0xbb, 0x00, 0x00), 
        pack888(0x77, 0x00, 0x00), pack888(0x33, 0x00, 0x00) };
    uint32_t blue888[] = { pack888(0x00, 0x00, 0xFF), pack888(0x00, 0x00, 0xbb),
        pack888(0x00, 0x00, 0x77), pack888(0x00, 0x00, 0x33) };
    if (bitmap.installPixels(imageInfo, (void*) red888, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    if (bitmap.installPixels(imageInfo, (void*) blue888, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
##
##

#Subtopic BGRA_8888

BGRA_8888 is a 32-bit word pixel encoding that contains eight bits of blue,
eight bits of green, eight bits of red, and eight bits of alpha. 

#Illustration

If paired with kPremul_SkAlphaType: blue, green, and red components are
premultiplied by the alpha value. If blue, green, or red is greater than alpha,
the drawn result is undefined.

If paired with kUnpremul_SkAlphaType: blue, green, red, and alpha components
may have any value. There may be a performance penalty with unpremultipled
pixels.

If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum; 
blue, green, and red components are fully opaque. If any alpha component is
less than 255, the drawn result is undefined.

On Little_Endian platforms, BGRA_8888 is the native Color_Type, and will have
the best performance. Use kN32_SkColorType to choose the best Color_Type for
the platform at compile time.

#Example
#Height 96
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kBGRA_8888_SkColorType, kPremul_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto pack8888 = [](unsigned a, unsigned r, unsigned g, unsigned b) -> uint32_t {
        return (b << 0) | (g << 8) | (r << 16) | (a << 24);
    };
    uint32_t red8888[] = { pack8888(0xFF, 0xFF, 0x0, 0x0), pack8888(0xFF, 0xbb, 0x0, 0x0), 
                           pack8888(0xFF, 0x99, 0x0, 0x0), pack8888(0xFF, 0x55, 0x0, 0x0) };
    uint32_t blue8888[] = { pack8888(0xFF, 0x0, 0x0, 0x0FF), pack8888(0xFF, 0x0, 0x0, 0x0bb),
                            pack8888(0xFF, 0x0, 0x0, 0x099), pack8888(0xFF, 0x0, 0x0, 0x055) };
    SkPixmap redPixmap(imageInfo, &red8888, imageInfo.minRowBytes());
    if (bitmap.writePixels(redPixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    SkPixmap bluePixmap(imageInfo, &blue8888, imageInfo.minRowBytes());
    if (bitmap.writePixels(bluePixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
##
##

#Subtopic RGBA_1010102

RGBA_1010102 is a 32-bit word pixel encoding that contains ten bits of red,
ten bits of green, ten bits of blue, and two bits of alpha. Possible alpha
values are zero: fully transparent; one: 33% opaque; two: 67% opaque;
three: fully opaque. 

#Illustration

If paired with kPremul_SkAlphaType: red, green, and blue components are
premultiplied by the alpha value. If red, green, or blue is greater than the
alpha replicated to ten bits, the drawn result is undefined.

If paired with kUnpremul_SkAlphaType: alpha, red, green, and blue components
may have any value. There may be a performance penalty with unpremultipled
pixels.

If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum; 
red, green, and blue components are fully opaque. If any alpha component is
less than 3, the drawn result is undefined.

#Example
#Bug 7645
#Height 96
#Platform cpu
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGBA_1010102_SkColorType, kOpaque_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto pack1010102 = [](unsigned r, unsigned g, unsigned b, unsigned a) -> uint32_t {
        return (r << 0) | (g << 10) | (b << 20) | (a << 30);
    };
    uint32_t redBits[] =  { pack1010102(0x3FF, 0x000, 0x000, 0x3), 
                            pack1010102(0x2ff, 0x000, 0x000, 0x3), 
                            pack1010102(0x1ff, 0x000, 0x000, 0x3), 
                            pack1010102(0x0ff, 0x000, 0x000, 0x3) };
    uint32_t blueBits[] = { pack1010102(0x000, 0x000, 0x3FF, 0x3), 
                            pack1010102(0x000, 0x000, 0x2ff, 0x3),
                            pack1010102(0x000, 0x000, 0x1ff, 0x3), 
                            pack1010102(0x000, 0x000, 0x0ff, 0x3) };
    if (bitmap.installPixels(imageInfo, (void*) redBits, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    SkPixmap bluePixmap(imageInfo, &blueBits, imageInfo.minRowBytes());
    if (bitmap.installPixels(imageInfo, (void*) blueBits, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
##
##

#Subtopic RGB_101010x

#Illustration

#Example
#Bug 7645
#Height 96
#Platform cpu
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGB_101010x_SkColorType, kOpaque_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto pack101010x = [](unsigned r, unsigned g, unsigned b) -> uint32_t {
        return (r << 0) | (g << 10) | (b << 20);
    };
    uint32_t redBits[] =  { pack101010x(0x3FF, 0x000, 0x000), pack101010x(0x2ff, 0x000, 0x000), 
    pack101010x(0x1ff, 0x000, 0x000), pack101010x(0x0ff, 0x000, 0x000) };
    uint32_t blueBits[] = { pack101010x(0x000, 0x000, 0x3FF), pack101010x(0x000, 0x000, 0x2ff),
    pack101010x(0x000, 0x000, 0x1ff), pack101010x(0x000, 0x000, 0x0ff) };
    if (bitmap.installPixels(imageInfo, (void*) redBits, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    SkPixmap bluePixmap(imageInfo, &blueBits, imageInfo.minRowBytes());
    if (bitmap.installPixels(imageInfo, (void*) blueBits, imageInfo.minRowBytes())) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
##
##

#Subtopic Gray_8

#Example
#Height 64
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kGray_8_SkColorType, kOpaque_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    uint8_t gray8[] = { 0xFF, 0xBB, 0x77, 0x33 };
    SkPixmap grayPixmap(imageInfo, &gray8, imageInfo.minRowBytes());
    if (bitmap.writePixels(grayPixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
##
##

#Subtopic RGBA_F16

#Illustration

#ToDo
FloatToHalf should be replaced with SkFloatToHalf if/when that's made public
##

#Example
#Height 96
#Function
union FloatUIntUnion {
    uint32_t fUInt;
    float    fFloat;
};

uint16_t FloatToHalf(float f) {
    static const FloatUIntUnion magic = { 15 << 23 };
    static const uint32_t round_mask = ~0xfffu;
    FloatUIntUnion floatUnion;
    floatUnion.fFloat = f;
    uint32_t sign = floatUnion.fUInt & 0x80000000u;
    floatUnion.fUInt ^= sign;
    floatUnion.fUInt &= round_mask;
    floatUnion.fFloat *= magic.fFloat;
    floatUnion.fUInt -= round_mask;
    return (floatUnion.fUInt >> 13) | (sign >> 16);
}
##

void draw(SkCanvas* canvas) {    
    canvas->scale(16, 16);
    SkBitmap bitmap;
    SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGBA_F16_SkColorType, kPremul_SkAlphaType);
    bitmap.allocPixels(imageInfo);
    SkCanvas offscreen(bitmap);
    offscreen.clear(SK_ColorGREEN);
    canvas->drawBitmap(bitmap, 0, 0);
    auto H = [](float c) -> uint16_t {
        return FloatToHalf(c);
    };
                             //     R        G        B        A
    uint16_t red_f16[][4] =  { { H(1.0f), H(0.0f), H(0.0f), H(1.0f) },
                               { H(.75f), H(0.0f), H(0.0f), H(1.0f) }, 
                               { H(.50f), H(0.0f), H(0.0f), H(1.0f) },
                               { H(.25f), H(0.0f), H(0.0f), H(1.0f) } };
    uint16_t blue_f16[][4] = { { H(0.0f), H(0.0f), H(1.0f), H(1.0f) },
                               { H(0.0f), H(0.0f), H(.75f), H(1.0f) }, 
                               { H(0.0f), H(0.0f), H(.50f), H(1.0f) },
                               { H(0.0f), H(0.0f), H(.25f), H(1.0f) } };
    SkPixmap redPixmap(imageInfo, red_f16, imageInfo.minRowBytes());
    if (bitmap.writePixels(redPixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 2, 2);
    }
    SkPixmap bluePixmap(imageInfo, blue_f16, imageInfo.minRowBytes());
    if (bitmap.writePixels(bluePixmap, 0, 0)) {
        canvas->drawBitmap(bitmap, 4, 4);
    }
}
##
##

#Subtopic Color_Type ##

# ------------------------------------------------------------------------------
#Subtopic YUV_ColorSpace
#Alias YUV_ColorSpace
#Enum SkYUVColorSpace
#Line # incomplete ##

#Code
    enum SkYUVColorSpace {
        kJPEG_SkYUVColorSpace,
        kRec601_SkYUVColorSpace,
        kRec709_SkYUVColorSpace,
        kLastEnum_SkYUVColorSpace = kRec709_SkYUVColorSpace,
    };
##

Describes the color space a YUV pixel.

#Const kJPEG_SkYUVColorSpace 0
Standard JPEG color space.
##
#Const kRec601_SkYUVColorSpace 1
SDTV standard Rec. 601 color space. Uses "studio swing" [16, 235] color
range. See http://en.wikipedia.org/wiki/Rec._601 for details.
##
#Const kRec709_SkYUVColorSpace 2
HDTV standard Rec. 709 color space. Uses "studio swing" [16, 235] color
range. See http://en.wikipedia.org/wiki/Rec._709 for details.
##

#Example
// incomplete
##

#SeeAlso incomplete

#Enum SkYUVColorSpace ##
#Subtopic YUV_ColorSpace ##

# ------------------------------------------------------------------------------
#EnumClass SkDestinationSurfaceColorMode
#Line # incomplete ##

#Code
    enum class SkDestinationSurfaceColorMode {
        kLegacy,
        kGammaAndColorSpaceAware,
    };
##

#Const kLegacy 0
##
#Const kGammaAndColorSpaceAware 1
##

#Example
// incomplete
##

#SeeAlso incomplete

#EnumClass SkDestinationSurfaceColorMode ##

# ------------------------------------------------------------------------------

#Struct SkImageInfo

Describes Image dimensions and pixel type.
Used for both source images and render-targets (surfaces).

#Subtopic Member_Function
#Populate
##

#Subtopic Related_Function
#Populate
##

# ------------------------------------------------------------------------------
#Subtopic Constructor
#Populate
##


#Method SkImageInfo()

#In Constructor
#Line # creates with zero dimensions, kUnknown_SkColorType, kUnknown_SkAlphaType ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo Make(int width, int height, SkColorType ct, SkAlphaType at,
                            sk_sp<SkColorSpace> cs = nullptr)
#In Constructor
#Line # creates Image_Info from dimensions, Color_Type, Alpha_Type, Color_Space ##

#Param width  incomplete ##
#Param height  incomplete ##
#Param ct  incomplete ##
#Param at  incomplete ##
#Param cs  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo MakeN32(int width, int height, SkAlphaType at,
                               sk_sp<SkColorSpace> cs = nullptr)
#In Constructor
#Line # creates Image_Info with Native_Color_Type ##

Sets Color_Type to kN32_SkColorType.

#Param width  incomplete ##
#Param height  incomplete ##
#Param at  incomplete ##
#Param cs  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo MakeS32(int width, int height, SkAlphaType at)

#In Constructor
#Line # creates Image_Info with Native_Color_Type, sRGB Color_Space ##
Creates Image_Info marked as sRGB with kN32_SkColorType swizzle.

#Param width  incomplete ##
#Param height  incomplete ##
#Param at  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo MakeN32Premul(int width, int height, sk_sp<SkColorSpace> cs = nullptr)

#In Constructor
#Line # creates Image_Info with Native_Color_Type, kPremul_SkAlphaType ##
Sets Color_Type to kN32_SkColorType, and the Alpha_Type to kPremul_SkAlphaType.

#Param width  incomplete ##
#Param height  incomplete ##
#Param cs  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo MakeN32Premul(const SkISize& size)

#In Constructor
#Param size  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo MakeA8(int width, int height)

#In Constructor
#Line # creates Image_Info with kAlpha_8_SkColorType, kPremul_SkAlphaType ##
#Param width  incomplete ##
#Param height  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo MakeUnknown(int width, int height)

#In Constructor
#Line # creates Image_Info with kUnknown_SkColorType, kUnknown_SkAlphaType ##
#Param width  incomplete ##
#Param height  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static SkImageInfo MakeUnknown()

#In Constructor
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##


# ------------------------------------------------------------------------------
#Subtopic Property
#Populate
#Line # metrics and attributes ##
##

#Method int width() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method int height() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkColorType colorType() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkAlphaType alphaType() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkColorSpace* colorSpace() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method sk_sp<SkColorSpace> refColorSpace() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method bool isEmpty() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method bool isOpaque() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkISize dimensions() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkIRect bounds() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method bool gammaCloseToSRGB() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkImageInfo makeWH(int newWidth, int newHeight) const
#In Constructor
#Line # creates Image_Info with changed dimensions ##
Creates Image_Info with the same Color_Type and Alpha_Type as this info,
but with the specified width and height.

#Param newWidth  incomplete ##
#Param newHeight  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkImageInfo makeAlphaType(SkAlphaType newAlphaType) const
#In Constructor
#Line # creates Image_Info with changed Alpha_Type ##
#Param newAlphaType  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkImageInfo makeColorType(SkColorType newColorType) const
#In Constructor
#Line # creates Image_Info with changed Color_Type ##
#Param newColorType  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method SkImageInfo makeColorSpace(sk_sp<SkColorSpace> cs) const
#In Constructor
#Line # creates Image_Info with changed Color_Space ##
#Param cs  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method int bytesPerPixel() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method int shiftPerPixel() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method uint64_t minRowBytes64() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method size_t minRowBytes() const
#In Property
#Line # incomplete ##
#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method size_t computeOffset(int x, int y, size_t rowBytes) const
#In Utility
#Line # incomplete ##
#Param x  incomplete ##
#Param y  incomplete ##
#Param rowBytes  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------
#Subtopic Operator
#Populate
##

#Method bool operator==(const SkImageInfo& other)_const

#Line # incomplete ##
#Param other  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method bool operator!=(const SkImageInfo& other)_const

#Line # incomplete ##
#Param other  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method void unflatten(SkReadBuffer& buffer)
#In Utility
#Line # incomplete ##
#Param buffer  incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method void flatten(SkWriteBuffer& buffer) const
#In Utility
#Line # incomplete ##
#Param buffer  incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method size_t computeByteSize(size_t rowBytes) const
#In Utility
#Line # incomplete ##
Returns the size (in bytes) of the image buffer that this info needs, given the specified
rowBytes. The rowBytes must be >= this->minRowBytes().
if (height == 0) {
return 0;
} else {
return (height - 1) * rowBytes + width * bytes_per_pixel.

If the calculation overflows this returns SK_MaxSizeT.

#Param rowBytes  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method size_t computeMinByteSize() const
#In Utility
#Line # incomplete ##
Returns the minimum size (in bytes) of the image buffer that this info needs.
If the calculation overflows, or if the height is 0, this returns 0.

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method static bool ByteSizeOverflowed(size_t byteSize)
#In Utility
#Line # incomplete ##
Returns true if the result of computeByteSize (or computeMinByteSize) overflowed

#Param byteSize  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method bool validRowBytes(size_t rowBytes) const
#In Utility
#Line # incomplete ##
#Param rowBytes  incomplete ##

#Return incomplete ##

#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------

#Method void reset()
#In Constructor
#Line # incomplete ##
#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

# ------------------------------------------------------------------------------
#Subtopic Utility
#Populate
#Line # rarely called management functions ##
##

#Method void validate() const
#In Utility
#Line # incomplete ##
#Example
// incomplete
##

#SeeAlso incomplete

#Method ##

#Struct SkImageInfo ##

#Topic Image_Info ##