[U-Boot] [PATCH v1 08/12] efi_loader: console support for color attributes

[Heinrich Schuchardt]

On 10/04/2017 10:54 PM, Rob Clark wrote:
> On Wed, Oct 4, 2017 at 2:53 PM, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>> On 09/10/2017 03:22 PM, Rob Clark wrote:
>>> Shell.efi uses this, and supporting color attributes makes things look
>>> nicer.  Map the EFI fg/bg color attributes to ANSI escape sequences.
>>> Not all colors have a perfect match, but spec just says "Devices
>>> supporting a different number of text colors are required to emulate the
>>> above colors to the best of the device’s capabilities".
>>>
>>> Signed-off-by: Rob Clark <robdclark at gmail.com>
>>> ---
>>>  include/efi_api.h            | 29 +++++++++++++++++++++++++++++
>>>  lib/efi_loader/efi_console.c | 30 ++++++++++++++++++++++++++++++
>>>  2 files changed, 59 insertions(+)
>>>
>>> diff --git a/include/efi_api.h b/include/efi_api.h
>>> index 87c8ffe68e..3cc1dbac2e 100644
>>> --- a/include/efi_api.h
>>> +++ b/include/efi_api.h
>>> @@ -426,6 +426,35 @@ struct simple_text_output_mode {
>>>       EFI_GUID(0x387477c2, 0x69c7, 0x11d2, \
>>>                0x8e, 0x39, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
>>>
>>> +#define EFI_BLACK                0x00
>>> +#define EFI_BLUE                 0x01
>>> +#define EFI_GREEN                0x02
>>> +#define EFI_CYAN                 0x03
>>> +#define EFI_RED                  0x04
>>> +#define EFI_MAGENTA              0x05
>>> +#define EFI_BROWN                0x06
>>> +#define EFI_LIGHTGRAY            0x07
>>> +#define EFI_BRIGHT               0x08
>>> +#define EFI_DARKGRAY             0x08
>>> +#define EFI_LIGHTBLUE            0x09
>>> +#define EFI_LIGHTGREEN           0x0a
>>> +#define EFI_LIGHTCYAN            0x0b
>>> +#define EFI_LIGHTRED             0x0c
>>> +#define EFI_LIGHTMAGENTA         0x0d
>>> +#define EFI_YELLOW               0x0e
>>> +#define EFI_WHITE                0x0f
>>> +#define EFI_BACKGROUND_BLACK     0x00
>>> +#define EFI_BACKGROUND_BLUE      0x10
>>> +#define EFI_BACKGROUND_GREEN     0x20
>>> +#define EFI_BACKGROUND_CYAN      0x30
>>> +#define EFI_BACKGROUND_RED       0x40
>>> +#define EFI_BACKGROUND_MAGENTA   0x50
>>> +#define EFI_BACKGROUND_BROWN     0x60
>>> +#define EFI_BACKGROUND_LIGHTGRAY 0x70
>>
>> Will we ever use these constants?
>>
> 
> possibly not, but it is useful to understand what is going on with
> efi->ansi mapping, so I would prefer to keep them.
> 
>>
>> Where are the comments explaining the defines below?
>>
>>> +
>>> +#define EFI_ATTR_FG(attr)        ((attr) & 0x0f)
>>
>> This saves 8 entries in the table below.
>> +#define EFI_ATTR_FG(attr)        ((attr) & 0x07)
>>
>>> +#define EFI_ATTR_BG(attr)        (((attr) >> 4) & 0x7)
>>
>> Add
>> #define EFI_ATTR_BOLD(attr) (((attr) >> 3) & 0x01)
>>
>>> +
>>>  struct efi_simple_text_output_protocol {
>>>       void *reset;
>>>       efi_status_t (EFIAPI *output_string)(
>>> diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
>>> index 2e13fdc096..fcd65ca488 100644
>>> --- a/lib/efi_loader/efi_console.c
>>> +++ b/lib/efi_loader/efi_console.c
>>> @@ -316,12 +316,42 @@ static efi_status_t EFIAPI efi_cout_set_mode(
>>>       return EFI_EXIT(EFI_SUCCESS);
>>>  }
>>>
>>> +static const struct {
>>> +     unsigned fg;
>>> +     unsigned bg;
>>> +} color[] = {
>>> +     { 30, 40 },     /* 0: black */
>>> +     { 34, 44 },     /* 1: blue */
>>> +     { 32, 42 },     /* 2: green */
>>> +     { 36, 46 },     /* 3: cyan */
>>> +     { 31, 41 },     /* 4: red */
>>> +     { 35, 45 },     /* 5: magenta */
>>> +     { 30, 40 },     /* 6: brown, map to black */
>>
>> This should be { 33, 43 }
>>
>>> +     { 37, 47 },     /* 7: light grey, map to white */
>>
>> The entries below are redundant.
>>
>>> +     { 37, 47 },     /* 8: bright, map to white */
>>> +     { 34, 44 },     /* 9: light blue, map to blue */
>>> +     { 32, 42 },     /* A: light green, map to green */
>>> +     { 36, 46 },     /* B: light cyan, map to cyan */
>>> +     { 31, 41 },     /* C: light red, map to red */
>>> +     { 35, 45 },     /* D: light magenta, map to magenta */
>>> +     { 33, 43 },     /* E: yellow */
>>> +     { 37, 47 },     /* F: white */
>>> +};
>>> +
> 
> I'm not totally convinced about mapping extra colors that UEFI defines
> to bold.. unless you have some example of prior-art for this on other
> platforms.

See
Standard ECMA-48 - Control Functions for Coded Character Sets
chapter 8.3.117 SGR - SELECT GRAPHIC RENDITION

1 - bold or increased intensity
22 - normal colour or normal intensity (neither bold nor faint)

You can easily experiment in your bash shell like this:

printf "\x1b[1;32;40m bold \x1b[22;32;40m normal\x1b[22;39;49m\n";

You will find that "bold" prints bold and bright in the KDE konsole and
xterm.

Using colors 90-97 as foreground colors produces only bright but not
bold in the KDE konsole and xterm:

printf "\x1b[92;40m bold \x1b[32;40m normal\x1b[22;39;49m\n";

But these codes are not defined in ECMA-48.

Best regards

Heinrich