mirror of
https://github.com/Ed94/Odin.git
synced 2026-06-17 11:22:22 -07:00
Jeroen van Rijn
107 lines
3.0 KiB
Odin
107 lines
3.0 KiB
Odin
package image
|
|
|
|
import "core:bytes"
|
|
|
|
Image :: struct {
|
|
width: int,
|
|
height: int,
|
|
channels: int,
|
|
depth: u8,
|
|
pixels: bytes.Buffer,
|
|
/*
|
|
Some image loaders/writers can return/take an optional background color.
|
|
For convenience, we return them as u16 so we don't need to switch on the type
|
|
in our viewer, and can just test against nil.
|
|
*/
|
|
background: Maybe([3]u16),
|
|
sidecar: any,
|
|
}
|
|
|
|
/*
|
|
Image_Option:
|
|
`.info`
|
|
This option behaves as `return_ihdr` and `do_not_decompress_image` and can be used
|
|
to gather an image's dimensions and color information.
|
|
|
|
`.return_header`
|
|
Fill out img.sidecar.header with the image's format-specific header struct.
|
|
If we only care about the image specs, we can set `return_header` +
|
|
`do_not_decompress_image`, or `.info`, which works as if both of these were set.
|
|
|
|
`.return_metadata`
|
|
Returns all chunks not needed to decode the data.
|
|
It also returns the header as if `.return_header` is set.
|
|
|
|
`do_not_decompress_image`
|
|
Skip decompressing IDAT chunk, defiltering and the rest.
|
|
|
|
`alpha_add_if_missing`
|
|
If the image has no alpha channel, it'll add one set to max(type).
|
|
Turns RGB into RGBA and Gray into Gray+Alpha
|
|
|
|
`alpha_drop_if_present`
|
|
If the image has an alpha channel, drop it.
|
|
You may want to use `alpha_premultiply` in this case.
|
|
|
|
NOTE: For PNG, this also skips handling of the tRNS chunk, if present,
|
|
unless you select `alpha_premultiply`.
|
|
In this case it'll premultiply the specified pixels in question only,
|
|
as the others are implicitly fully opaque.
|
|
|
|
`alpha_premultiply`
|
|
If the image has an alpha channel, returns image data as follows:
|
|
RGB *= A, Gray = Gray *= A
|
|
|
|
`blend_background`
|
|
If a bKGD chunk is present in a PNG, we normally just set `img.background`
|
|
with its value and leave it up to the application to decide how to display the image,
|
|
as per the PNG specification.
|
|
|
|
With `blend_background` selected, we blend the image against the background
|
|
color. As this negates the use for an alpha channel, we'll drop it _unless_
|
|
you also specify `alpha_add_if_missing`.
|
|
|
|
Options that don't apply to an image format will be ignored by their loader.
|
|
*/
|
|
|
|
Option :: enum {
|
|
info = 0,
|
|
do_not_decompress_image,
|
|
return_header,
|
|
return_metadata,
|
|
alpha_add_if_missing,
|
|
alpha_drop_if_present,
|
|
alpha_premultiply,
|
|
blend_background,
|
|
}
|
|
Options :: distinct bit_set[Option];
|
|
|
|
PNG_Error :: enum {
|
|
Invalid_PNG_Signature,
|
|
IHDR_Not_First_Chunk,
|
|
IHDR_Corrupt,
|
|
IDAT_Missing,
|
|
IDAT_Must_Be_Contiguous,
|
|
IDAT_Corrupt,
|
|
PNG_Does_Not_Adhere_to_Spec,
|
|
PLTE_Encountered_Unexpectedly,
|
|
PLTE_Invalid_Length,
|
|
TRNS_Encountered_Unexpectedly,
|
|
BKGD_Invalid_Length,
|
|
Invalid_Image_Dimensions,
|
|
Unknown_Color_Type,
|
|
Invalid_Color_Bit_Depth_Combo,
|
|
Unknown_Filter_Method,
|
|
Unknown_Interlace_Method,
|
|
}
|
|
|
|
|
|
/*
|
|
Functions to help with image buffer calculations
|
|
*/
|
|
|
|
compute_buffer_size :: proc(width, height, channels, depth: int, extra_row_bytes := int(0)) -> (size: int) {
|
|
|
|
size = ((((channels * width * depth) + 7) >> 3) + extra_row_bytes) * height;
|
|
return;
|
|
} |