init.pre

! Image loading helpers for Prefix
! Backed by image/image.c.
!
! The returned tensor layout is [column][row][channel] (width, height, channel)
! in user code. Channels are ordered r, g, b, a and values are 0..255.

EXTEND(EXTENSION: win32)

EXTEND(EXTENSION: image)

IMPORT(path)

FUNC TNS LOAD(STR img_path){
    STR ext = path.EXTNAME(img_path)
    IF(EQ(ext, "png")){
        RETURN(LOAD_PNG(img_path))
    } ELSEIF (OR(EQ(ext, "jpg"),EQ(ext, "jpeg"))){
        RETURN(LOAD_JPEG(img_path))
    } ELSEIF (EQ(ext, "bmp")){
        RETURN(LOAD_BMP(img_path))
    } ELSE {
        THROW("Unsupported image format: ",ext)
    }
}

FUNC INT WIDTH(TNS img){
    RETURN(TLEN(img, 0d1))
}

FUNC INT HEIGHT(TNS img){
    RETURN(TLEN(img, 0d2))
}

FUNC INT CHANNELS(TNS img){
    RETURN(TLEN(img, 0d3))
}

FUNC TNS R(TNS img){
    RETURN(img[*, *, 0d1])
}

FUNC TNS G(TNS img){
    RETURN(img[*, *, 0d2])
}

FUNC TNS B(TNS img){
    RETURN(img[*, *, 0d3])
}

FUNC TNS A(TNS img){
    RETURN(img[*, *, 0d4])
}

FUNC TNS PIXEL(TNS img, INT x, INT y){
    RETURN(img[x, y, *])
}

FUNC INT PIXEL_R(TNS img, INT x, INT y){
    RETURN(img[x, y, 0d1])
}

FUNC INT PIXEL_G(TNS img, INT x, INT y){
    RETURN(img[x, y, 0d2])
}

FUNC INT PIXEL_B(TNS img, INT x, INT y){
    RETURN(img[x, y, 0d3])
}

FUNC INT PIXEL_A(TNS img, INT x, INT y){
    RETURN(img[x, y, 0d4])
}

FUNC TNS FLIP_V(TNS img){
    RETURN(TFLIP(img, 0d1))
}

FUNC TNS FLIP_H(TNS img){
    RETURN(TFLIP(img, 0d2))
}

FUNC TNS INVERT(TNS img){
    TNS return = MSUB(TNS(SHAPE(img), 0xFF), img)
    return[*, *, 0d4] = img[*, *, 0d4] ! Preserve alpha
    POP(return)
}

FUNC TNS RECT(TNS img, INT x, INT y, INT width, INT height, TNS color, INT fill, INT thickness){
    TNS pts = [ ^
        [x, y], ^
        [ADD(x, SUB(width, 0d1)), y], ^
        [ADD(x, SUB(width, 0d1)), ADD(y, SUB(height, 0d1))], ^
        [x, ADD(y, SUB(height, 0d1))], ^
        [x, y] ^
    ]
    RETURN(POLYGON(img, pts, color, fill, thickness))
}

FUNC TNS RECTANGLE(TNS img, INT x, INT y, INT width, INT height, TNS color, INT fill, INT thickness){
    RETURN(RECT(img, x, y, width, height, color, fill, thickness))
}

FUNC TNS FILL_RECT(TNS img, INT x, INT y, INT width, INT height, TNS color){
    RETURN(RECT(img, x, y, width, height, color, 0d1, 0d1))
}

FUNC TNS FILL_ELLIPSE(TNS img, TNS center, INT rx, INT ry, TNS color){
    RETURN(ELLIPSE(img, center, rx, ry, color, 0d1, 0d1))
}
 
FUNC TNS SQUARE(TNS img, INT x, INT y, INT size, TNS color, INT fill, INT thickness){
    RETURN(RECT(img, x, y, size, size, color, fill, thickness))
}

FUNC TNS CIRCLE(TNS img, TNS center, INT radius, TNS color, INT fill, INT thickness){
    RETURN(ELLIPSE(img, center, radius, radius, color, fill, thickness))
}

FUNC TNS CROP(TNS img, TNS corners){
    IF(NEQ(SHAPE(corners), [0d4, 0d2])){
        THROW("CROP corners must be a 0d4 by 0d2 tensor: [[tl_x, tl_y], [tr_x, tr_y], [bl_x, bl_y], [br_x, br_y]]")
    }
    RETURN(img[MIN(corners[*, 0d1]):MAX(corners[*, 0d1]), MIN(corners[*, 0d2]):MAX(corners[*, 0d2]), *])
}

FUNC BOOL SHOW(TNS img){
    ! Save the image to the provided path and open it with the system default
    ! viewer on Windows. `img_path` is treated as the target file path.
    STR img_path = "C:/Windows/Temp/tmp_img.png"
    SAVE_PNG(img, img_path, 0d0)
    ! ShellExecuteW(hwnd, operation, file, params, dir, showcmd)
    ! Use NULL hwnd (0), operation "open", empty params and dir, showcmd=1
    win32.WIN_CALL("shell32", "ShellExecuteW", "PSSSSI", "P", 0d0, "open", img_path, "", "", 0d1)
    DEL(img_path)
    RETURN(FALSE)
}