Read from File
The PoCo.app only support that extension word has ".poco".
And, the PoCo.app assume that reaing file is stored by the PoCo.app.
The PoCo.app can obtain data-stream which are folloing:
| CHUNK | Name | Description |
|---|---|---|
| IHDR | Image Header | The color type must be specified 3(indexed color), and non-interlace must be specified. Image size(width and height) obtain from this chunk. |
| iCCP | Embedded ICC Profile | The information of color space is the ICC profile. That is, the use of ICC profile is specified(checked) on the document setting. Note that the PoCo.app does not use ICC profile information, so any data in the iCCP chunk would be ignored. |
| sRGB | Standard RGB Color Space | The information of color space is NOT the ICC profile. That is, the use of ICC profile is not specified(unchecked) on the document setting, which specified value is retained as SRGB value. |
| gAMA | Image Gamma | Stored value is retained as gamma value on the document setting. |
| cHRM | Primary Chromaticities and White Point | Stored values are retained as chromaticity settings on the document setting. |
| pHYs | Physical Pixel Dimensions | Stored value is treated as resolution(DPI). |
| PLTE | Palette | Stored values are obtained from first to last one by one. When there are less than 256 colors, obtaining is so far.(colors of absent are default color within the PoCo.app.) |
| tRNS | Transparency | Stored values are obtained for which each color have the tranparency of the auxiliary attributes of a color. A value interprets 0 as transparency, a value interprets 255 as opaqueness. Intermediate values are interpreted as opaqueness except that that values are stored to R, G, and B if a corresponding color is non-colored.(that is, tRNS chunk interpretation when grayscale treat as transparent on the preferences panel is specified.) If the number of element is less than 256, obtaining is so far.(by default, that colors are opaqueness.) |
| drOP | Not use Private chunk |
Stored values are obtained for which each color have the not-use(exclude color) of the auxiliary attributes of a color. |
| maSK | Mask Private chunk |
Stored values are obtained for which each color have the mask(prohibit overriding) of the auxiliary attributes of a color. |
| bKGD | Background Color | Stored value is retained as the background color on the document setting. |
| cpAT | Color Pattern Private chunk |
A stored data is treated as the color pattern. The data-stream must be contain width, and followed by height, and followed by pattern(image) which is compressed by zlib deflate. If the number of the cpAT chunk is greater than 16, that chunks are ignored. |
| ilAY | Image Layer Private Chunk |
A stored data is treated as the image layer. The data-stream start visible attribute, followed by editable attribute, followed by name(null-terminate), followed by width, followed by height, and followed by image which is compressed by zlib deflate. |
| IDAT | Image Data | When a file is stored by the PoCo.app, this chunk is ignored. Except that on the condition that read the normally PNG file is corresponded, the IDAT chunk is treated as single image layer. |
| IEND | Image Trailer | The end of the PNG data-stream. The PoCo.app does not read beyond datas. |
