SkMasks.cpp File Reference

#include "src/core/SkMasks.h"
#include "include/private/base/SkDebug.h"

Go to the source code of this file.

Functions
static uint8_t	convert_to_8 (uint8_t component, uint32_t n)
static uint8_t	get_comp (uint32_t pixel, uint32_t mask, uint32_t shift, uint32_t size)
static SkMasks::MaskInfo	process_mask (uint32_t mask)

Variables
static constexpr uint8_t	n_bit_to_8_bit_lookup_table []

Function Documentation

convert_to_8()

static uint8_t convert_to_8 ( uint8_t  component, uint32_t  n  )

static

Definition at line 49 of file SkMasks.cpp.

                                                           {
    if (0 == n) {
        return 0;
    } else if (8 > n) {
        return n_bit_to_8_bit_lookup_table[(1 << n) - 2 + component];
    } else {
        SkASSERT(8 == n);
        return component;
    }
}

get_comp()

static uint8_t get_comp ( uint32_t  pixel, uint32_t  mask, uint32_t  shift, uint32_t  size  )

static

Definition at line 60 of file SkMasks.cpp.

                                       {
    return convert_to_8((pixel & mask) >> shift, size);
}

process_mask()

static SkMasks::MaskInfo process_mask ( uint32_t  mask )

static

Definition at line 88 of file SkMasks.cpp.

                                                   {
    // Determine properties of the mask
    uint32_t tempMask = mask;
    uint32_t shift = 0;
    uint32_t size = 0;
    if (tempMask != 0) {
        // Count trailing zeros on masks
        for (; (tempMask & 1) == 0; tempMask >>= 1) {
            shift++;
        }
        // Count the size of the mask
        for (; tempMask & 1; tempMask >>= 1) {
            size++;
        }
        // Verify that the mask is continuous
        if (tempMask) {
            SkDebugf("Warning: Bit mask is not continuous.\n");
            // Finish processing the mask
            for (; tempMask; tempMask >>= 1) {
                size++;
            }
        }
        // Truncate masks greater than 8 bits
        if (size > 8) {
            shift += size - 8;
            size = 8;
            mask &= 0xFF << shift;
        }
    }
 
    return { mask, shift, size };
}

Variable Documentation

n_bit_to_8_bit_lookup_table

constexpr uint8_t n_bit_to_8_bit_lookup_table[]

staticconstexpr

Initial value:

= {
    
    0, 255,
    
    0, 85, 170, 255,
    
    0, 36, 73, 109, 146, 182, 219, 255,
    
    0, 17, 34, 51, 68, 85, 102, 119, 136, 153, 170, 187, 204, 221, 238, 255,
    
    0, 8, 16, 25, 33, 41, 49, 58, 66, 74, 82, 90, 99, 107, 115, 123, 132, 140,
    148, 156, 165, 173, 181, 189, 197, 206, 214, 222, 230, 239, 247, 255,
    
    0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 45, 49, 53, 57, 61, 65, 69, 73,
    77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 130, 134, 138,
    142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190, 194, 198,
    202, 206, 210, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251, 255,
    
    0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38,
    40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76,
    78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110,
    112, 114, 116, 118, 120, 122, 124, 126, 129, 131, 133, 135, 137, 139, 141,
    143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171,
    173, 175, 177, 179, 181, 183, 185, 187, 189, 191, 193, 195, 197, 199, 201,
    203, 205, 207, 209, 211, 213, 215, 217, 219, 221, 223, 225, 227, 229, 231,
    233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253, 255
}

Definition at line 16 of file SkMasks.cpp.