
<<Imager32BitABufferImpl.mesa>>
<<Copyright © 1984 by Xerox Corporation.  All rights reserved.>>
<<Frank Crow, July 30, 1984 5:50:05 pm PDT>>
<<>>
DIRECTORY 
Imager                USING [Error, Context], 
ImagerBasic            USING [DeviceRectangle, Color, ColorRep], 
ImagerDisplay        USING [DisplayClass, DisplayClassRep, DisplayData, CreateImagerClass], 
ImagerStdColorDisplay    USING [MapInitProc, Create, ApplyMask, GetDisplay, PinPixelMap,
                                     ReleasePixelMap, LoadColorMap, DoUnderLock],
ImagerManhattan    USING [Polygon], 
ImagerMasks            USING [Mask], 
ImagerPrivate        USING [Class, RegisterDevice], 
ColorModels            USING [Calibration],
ConstantColors        USING [ColorToRGB, black, white, red, cyan, green, magenta, blue, yellow,
                                 orange, purple, brown, grey, darkGrey, veryLightGrey, lightGrey,
                                 veryDarkGrey, NameToColor],
Terminal                USING [ColorMode, Current, GetColorBitmapState, SetColor, Virtual], 
Rope                    USING [ROPE],
Real                    USING [FixC];

Imager32BitABufferImpl: CEDAR MONITOR
IMPORTS Imager, ImagerDisplay, ImagerPrivate, ConstantColors, Terminal, Real, 
           ImagerStdColorDisplay
~ BEGIN
<<This implements an 24-bit-per-pixel color display with an additional 8-bit Alpha buffer for antialiasing.>>

DisplayClass: TYPE ~ ImagerDisplay.DisplayClass;
DisplayClassRep: TYPE ~ ImagerDisplay.DisplayClassRep;
DisplayData: TYPE ~ ImagerDisplay.DisplayData;
Color: TYPE ~ ImagerBasic.Color;
ColorRep: TYPE ~ ImagerBasic.ColorRep;
ConstantColor: TYPE = REF ColorRep.constant;
Mask: TYPE ~ ImagerMasks.Mask;

on: BOOLEAN ~ TRUE;
off: BOOLEAN ~ FALSE;
lgBitsPerPixel: NAT ~ 5;

vt: Terminal.Virtual;
mode: Terminal.ColorMode ~ [full: TRUE, bitsPerPixelChannelA: 0, bitsPerPixelChannelB: 0];
colorCalibration: ColorModels.Calibration;


alpha32BitDisplayClass: ImagerDisplay.DisplayClass ~ NEW[ImagerDisplay.DisplayClassRep _ [
displayType: $alpha32bpp,
viewUnitsPerPixel: 1,
Create: Create,
ApplyMask: ApplyMask,
DoUnderLock: ImagerStdColorDisplay.DoUnderLock
]];

ColorDisplayError: PUBLIC ERROR [reason: ATOM] ~ CODE;

Create: PROC [displayClass: DisplayClass, creationData: REF]
RETURNS [displayData: DisplayData] ~ {
ImagerStdColorDisplay.GetDisplay[vt, $unchanged, mode, SetUpColorMap];
displayData _ ImagerStdColorDisplay.Create[vt, displayClass, creationData, lgBitsPerPixel];
};

ApplyMask: PROC [displayData: DisplayData, color: Color, mask: Mask, 
                        sTranslate, fTranslate: INTEGER] ~ {
ImagerStdColorDisplay.ApplyMask[displayData, color, mask, sTranslate, fTranslate, CacheColor];
};

SpecialOp: PROC[context: Imager.Context, op: ATOM, data: REF] RETURNS[REF] ~ {
SELECT op FROM
$DisplayContext =>  { -- Pin a pixel map to the color display, replace what was there before.  
IF vt.GetColorBitmapState # displayed THEN                         -- turn on color display
ImagerStdColorDisplay.GetDisplay[vt, $aOn, mode, SetUpColorMap];
MergeRGMaps[NARROW[context.data, ImagerDisplay.DisplayData], data];  --Interleave R&G
ImagerStdColorDisplay.PinPixelMap[vt, NARROW[context.data, ImagerDisplay.DisplayData] ];
};
$UnDisplayContext => ImagerStdColorDisplay.ReleasePixelMap[vt, 
                                             NARROW[context.data, ImagerDisplay.DisplayData]];
$LoadColorMap => ImagerStdColorDisplay.LoadColorMap[vt, data];
$TurnOffRGMerging => MergingOn _ FALSE;    -- client merging of Red and Grn pixelmaps
$TurnOnRGMerging => MergingOn _ TRUE;    -- auto merging of Red and Grn pixelmaps
$MergeRGMaps => MergeRGMaps[NARROW[context.data, ImagerDisplay.DisplayData], data];
ENDCASE => Imager.Error[$UnimplementedSpecialOp];
RETURN[ NIL ];
};

SetUpColorMap: ImagerStdColorDisplay.MapInitProc ~ {
FOR i: NAT IN [0..256) DO
j: NAT _ Real.FixC[RealFns.Power[i/256.0, .43] * 256.0];    -- Linearize power law display
vt.SetRedMap[i, j];
vt.SetGreenMap[i, j];
vt.SetBlueMap[i, j];
ENDLOOP;
};

Init: PROC[] ~ {
alpha32BitImagerClass: ImagerPrivate.Class ~
     ImagerDisplay.CreateImagerClass[alpha32BitDisplayClass];        -- pick up Imager class record
alpha32BitImagerClass.SpecialOp _ SpecialOp;                    -- modify procedure bindings
ImagerPrivate.RegisterDevice[alpha32BitImagerClass];            -- register device class
vt _ Terminal.Current[];
};

Init[];

END.