| // Copyright (C) 2015 The Android Open Source Project |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package image |
| |
| type fmtAlpha struct{} |
| |
| func (fmtAlpha) String() string { return "Alpha" } |
| func (fmtAlpha) Check(d []byte, w, h int) error { return checkSize(d, w, h, 8) } |
| |
| // Alpha returns a format containing a single 8-bit alpha channel per pixel. |
| func Alpha() Format { return fmtAlpha{} } |
| |
| func init() { |
| RegisterConverter(Alpha(), RGBA(), |
| func(src []byte, width, height int) ([]byte, error) { |
| dst, i, j := make([]byte, width*height*4), 0, 0 |
| for y := 0; y < height; y++ { |
| for x := 0; x < width; x++ { |
| dst[j+0], dst[j+1], dst[j+2], dst[j+3] = 255, 255, 255, src[i] |
| i++ |
| j += 4 |
| } |
| } |
| return dst, nil |
| }) |
| } |