
    <<ImagerTerminalImpl.mesa>>
        <<Copyright © 1984, 1985 by Xerox Corporation.  All rights reserved.>>
        <<Doug Wyatt, July 22, 1985 3:29:47 pm PDT>>
        <<Michael Plass, July 22, 1985 11:33:48 am PDT>>
    <<>>
    DIRECTORY
        Imager USING [Context],
        ImagerCache USING [GetNamedCache, Ref],
        ImagerColorMap USING [SetStandardColorMap],
        ImagerDevice USING [Device, DeviceBox],
        ImagerDitheredDevice USING [ContextFromColorTerminal],
        ImagerFastShow USING [Create],
        ImagerPixelMap USING [PixelMap, PixelMapRep],
        ImagerRaster USING [AmbushDevice, Ambusher, AmbusherRep, Create, NewBitmapDevice, NewColor24Device],
        ImagerTerminal USING [],
        Terminal;

    ImagerTerminalImpl: CEDAR PROGRAM
    IMPORTS ImagerCache, ImagerColorMap, ImagerDitheredDevice, ImagerFastShow, ImagerRaster, Terminal
    EXPORTS ImagerTerminal
    ~ BEGIN

    Context: TYPE ~ Imager.Context;

    Lg: PROC [n: NAT] RETURNS [NAT] ~ {
        RETURN[SELECT n FROM 1 => 0, 2 => 1, 4 => 2, 8 => 3, 16 => 4, ENDCASE => ERROR]
        };

    PixelMapFromFrameBuffer: PROC [frameBuffer: Terminal.FrameBuffer] 
    RETURNS [ImagerPixelMap.PixelMap] ~ {
        refRep: REF ImagerPixelMap.PixelMapRep ~ NEW[ImagerPixelMap.PixelMapRep _ [
            ref: frameBuffer,
            pointer: frameBuffer.base,
            words: INT[frameBuffer.wordsPerLine]*INT[frameBuffer.height],
            lgBitsPerPixel: Lg[frameBuffer.bitsPerPixel],
            rast: frameBuffer.wordsPerLine,
            lines: frameBuffer.height
            ]];
        frame: ImagerPixelMap.PixelMap ~ [
            sOrigin: 0, fOrigin: 0, sMin: 0, fMin: 0,
            sSize: frameBuffer.height, fSize: frameBuffer.width, refRep: refRep
            ];
        RETURN[frame];
        };

    bitmapCacheID: ATOM ~ $Bitmap;
    bitmapCacheSize: NAT ~ 4000;
    bitmapRastWeight: REAL ~ 2.0;

    BWContext: PUBLIC PROC [vt: Terminal.Virtual, pixelUnits: BOOL] RETURNS [Context] ~ {
        frameBuffer: Terminal.FrameBuffer ~ Terminal.GetBWFrameBuffer[vt];
        RETURN[ImagerFastShow.Create[pm: PixelMapFromFrameBuffer[frameBuffer], pixelsPerInch: vt.bwPixelsPerInch, pixelUnits: pixelUnits, 
        fontTuner: NIL]];
        };

    colorCacheID: ATOM ~ $ColorDisplay;
    colorCacheSize: NAT ~ 4000;
    colorRastWeight: REAL ~ 0.0;

    OneBitPerPixelMasker: PROC [self: ImagerRaster.Ambusher, box: ImagerDevice.DeviceBox, action: PROC] ~ {
        vt: Terminal.Virtual ~ NARROW[self.data];
        Terminal.ModifyColorFrame[vt: vt, action: action, xmin: box.fmin, ymin: box.smin, xmax: box.fmax, ymax: box.smax];
        };

    ColorContext: PUBLIC PROC [vt: Terminal.Virtual, pixelUnits: BOOL] RETURNS [Context] ~ {
        mode: Terminal.ColorMode ~ Terminal.GetColorMode[vt];
        IF Terminal.GetColorBitmapState[vt]=none THEN RETURN[NIL];
        IF mode.full THEN {
            device: ImagerDevice.Device ~ ImagerRaster.NewColor24Device[vt];
            colorFontCache: ImagerCache.Ref ~ ImagerCache.GetNamedCache[
            atom: colorCacheID, createSize: colorCacheSize];
            [] _ Terminal.SetColorCursorPresentation[vt, onesAreBlack];
            RETURN[ImagerRaster.Create[device: device, pixelUnits: pixelUnits, 
            fontCache: colorFontCache, rastWeight: colorRastWeight]];
            }
        ELSE {
            frameBuffer: Terminal.FrameBuffer ~ Terminal.GetColorFrameBufferA[vt];
            IF mode.bitsPerPixelChannelA = 1 THEN {
                frame: ImagerPixelMap.PixelMap ~ PixelMapFromFrameBuffer[frameBuffer];
                ambusher: ImagerRaster.Ambusher ~ NEW[ImagerRaster.AmbusherRep _ [
                    maskProc: OneBitPerPixelMasker,
                    device: ImagerRaster.NewBitmapDevice[
                    frame: frame, pixelsPerInch: vt.colorPixelsPerInch],
                    data: vt
                    ]];
                device: ImagerDevice.Device ~ ImagerRaster.AmbushDevice[ambusher];
                bitmapFontCache: ImagerCache.Ref ~ ImagerCache.GetNamedCache[
                atom: bitmapCacheID, createSize: bitmapCacheSize];
                [] _ Terminal.SetColorCursorPresentation[vt, onesAreWhite];
                    <<They are really black because we have an unconventional frame buffer.>>
                RETURN[ImagerRaster.Create[device: device, pixelUnits: pixelUnits, 
                fontCache: bitmapFontCache, rastWeight: bitmapRastWeight]];
                }
            ELSE {
                [] _ Terminal.SetColorCursorPresentation[vt, onesAreBlack];
                RETURN[ImagerDitheredDevice.ContextFromColorTerminal[vt, pixelUnits]];
                };
            };
        };

    SetStandardColorMap: PUBLIC PROC [vt: Terminal.Virtual] ~ {
        ImagerColorMap.SetStandardColorMap[vt];
        };

    END.