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

Heinrich Schuchardt
2017-10-04T23:53:04Z

On 10/05/2017 01:19 AM, Rob Clark wrote:
> On Wed, Oct 4, 2017 at 6:01 PM, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote:
>> On 10/04/2017 10:54 PM, Rob Clark wrote:
>>> On Wed, Oct 4, 2017 at 2:53 PM, Heinrich Schuchardt <xypron.glpk@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@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.
>
> but I think we don't want (potential) font changes, just color changes..
>
> if you can find the code in edk2 that does this, I guess it would be a
> reasonable precedent to follow.. but if not I wanted to avoid things
> that might be specific to particular terminal emulators, since I
> wasn't really looking forward to testing them all. Otherwise I'd just
> rely on the extension that allowed 256 colors..
>
> BR,
> -R

The same problem seems has led the EDK folks to a similar solution.

See
MdeModulePkg/Universal/Console/TerminalDxe/TerminalConOut.c

Everything starts with this array:

{ ESC, '[', '0', 'm', ESC, '[', '4', '0', 'm', ESC, '[', '4', '0', 'm', 0 };

The first '0' is replaced by either 0 or 1 depending on brightness.

mSetAttributeString[BRIGHT_CONTROL_OFFSET] =
(CHAR16) ('0' + BrightControl);

The first '4', '0' is replaced by the foreground color.
The second '4', '0' is replaced by the background color.

ECMA 48 says:

0 - default rendition, cancels the effect of any preceding SGR

So you can use this instead of 22.

Best regards

Heinrich

>
>> 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
>>
>