ce82ff7e2b
* Add psd preview support * Adding required vendor files * Adding oov/psd license to NOTICE.txt file * Adding the license notice for gopherjs to the NOTICE.txt Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
109 строки
2.9 KiB
Go
109 строки
2.9 KiB
Go
package psd
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import (
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"errors"
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"io"
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)
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// ImageResource represents the image resource that is used in psd file.
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type ImageResource struct {
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Name string
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Data []byte
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}
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func readImageResource(r io.Reader) (resMap map[int]ImageResource, read int, err error) {
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if Debug != nil {
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Debug.Println("start - image resources section")
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}
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// Image Resources Section
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// http://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577409_69883
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var l int
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b := make([]byte, 6)
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if l, err = io.ReadFull(r, b[:4]); err != nil {
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return nil, 0, err
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}
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read += l
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imageResourceLen := int(readUint32(b, 0))
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if imageResourceLen == 0 {
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return map[int]ImageResource{}, read, nil
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}
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resMap = map[int]ImageResource{}
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// Image Resource Blocks
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// http://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577409_46269
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var id int
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for read < imageResourceLen {
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var res ImageResource
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// Signature: '8BIM'
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if l, err = io.ReadFull(r, b[:6]); err != nil {
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return nil, read, err
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}
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read += l
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if string(b[:4]) != "8BIM" {
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return nil, read, errors.New("psd: invalid image resource signature")
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}
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// Unique identifier for the resource.
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// Image resource IDs contains a list of resource IDs used by Photoshop.
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// http://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577409_38034
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id = int(readUint16(b, 4))
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// Name: Pascal string, padded to make the size even
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// (a null name consists of two bytes of 0)
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if res.Name, l, err = readPascalString(r); err != nil {
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return nil, read, err
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}
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read += l
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if l, err = adjustAlign2(r, l); err != nil {
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return nil, read, err
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}
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read += l
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// The resource data, described in the sections on the individual resource types.
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// It is padded to make the size even.
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if l, err = io.ReadFull(r, b[:4]); err != nil {
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return nil, read, err
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}
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read += l
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res.Data = make([]byte, readUint32(b, 0))
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if l, err = io.ReadFull(r, res.Data); err != nil {
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return nil, read, err
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}
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read += l
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if l, err = adjustAlign2(r, l); err != nil {
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return nil, read, err
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}
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read += l
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if Debug != nil {
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Debug.Printf(" id: %04x(%d) name: %s dataLen: %d", id, id, res.Name, len(res.Data))
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}
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resMap[id] = res
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}
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if Debug != nil {
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Debug.Println("end - image resources section")
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}
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return resMap, read, nil
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}
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func hasAlphaID0(Res map[int]ImageResource) bool {
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// http://www.adobe.com/devnet-apps/photoshop/fileformatashtml/#50577409_38034
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// 0x041D(1053) | (Photoshop 6.0) Alpha Identifiers.
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// 4 bytes of length, followed by 4 bytes each for every alpha identifier.
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//
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// This description is probably a little different from the actual structure.
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// "4 bytes of length" is included in Image Resource Blocks structure, not in the resource data block.
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// so alpha identifier appears from the head in the resource data block.
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aid, ok := Res[0x041D]
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if !ok {
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return true
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}
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for i, ln := 0, len(aid.Data); i < ln; i += 4 {
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if readUint32(aid.Data, i) == 0 {
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return true
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}
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}
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return false
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}
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