Show alt text character map

README.md

@@ -159,6 +159,7 @@ Line:
 - F7: Show the video mode and a split screen with the views for NTSC color TV, page 1, page 2 and extra info.
 - F10: Cycle character generator code pages. Only if the character generator ROM has more than one 2Kb page.
 - Ctrl-F10: Show the charater map for the current character generator page.
+- Shift-F10: When showing the character map, use altText.
 - F11: Toggle on and off the trace to console of the CPU execution
 - F12: Save a screen snapshot to a file `snapshot.png`
 - Pause: Pause the emulation

frontend/a2sdl/main.go

@@ -91,7 +91,7 @@ func sdlRun(a *izapple2.Apple2) {
 		if !a.IsPaused() {
 			var img *image.RGBA
 			if kp.showCharGen {
-				img = screen.SnapshotCharacterGenerator(a)
+				img = screen.SnapshotCharacterGenerator(a, kp.showAltText)
 				window.SetTitle(fmt.Sprintf("%v character map", a.Name))
 			} else if kp.showPages {
 				img = screen.SnapshotParts(a, screen.ScreenModeNTSC)

frontend/a2sdl/sdlKeyboard.go

@@ -14,6 +14,7 @@ type sdlKeyboard struct {
 
 	showPages   bool
 	showCharGen bool
+	showAltText bool
 }
 
 func newSDLKeyBoard(a *izapple2.Apple2) *sdlKeyboard {
@@ -43,6 +44,7 @@ func (k *sdlKeyboard) putKey(keyEvent *sdl.KeyboardEvent) {
 
 	key := keyEvent.Keysym
 	ctrl := key.Mod&sdl.KMOD_CTRL != 0
+	shift := key.Mod&sdl.KMOD_SHIFT != 0
 
 	if ctrl {
 		if key.Sym >= 'a' && key.Sym <= 'z' {
@@ -103,6 +105,8 @@ func (k *sdlKeyboard) putKey(keyEvent *sdl.KeyboardEvent) {
 	case sdl.K_F10:
 		if ctrl {
 			k.showCharGen = !k.showCharGen
+		} else if shift {
+			k.showAltText = !k.showAltText
 		} else {
 			k.a.SendCommand(izapple2.CommandNextCharGenPage)
 		}

screen/snapshots.go

@@ -40,6 +40,7 @@ func snapshotByMode(vs VideoSource, videoMode uint16, screenMode int) *image.RGB
 	videoBase := videoMode & VideoBaseMask
 	mixMode := videoMode & VideoMixTextMask
 	isSecondPage := (videoMode & VideoSecondPage) != 0
+	isAltText := (videoMode & VideoAltText) != 0
 
 	var lightColor color.Color = color.White
 	if screenMode == ScreenModeGreen {
@@ -53,13 +54,13 @@ func snapshotByMode(vs VideoSource, videoMode uint16, screenMode int) *image.RGB
 	var ntscMask *image.Alpha
 	switch videoBase {
 	case VideoText40:
-		snap = snapshotText40(vs, isSecondPage, lightColor)
+		snap = snapshotText40(vs, isSecondPage, isAltText, lightColor)
 		applyNTSCFilter = false
 	case VideoText80:
-		snap = snapshotText80(vs, isSecondPage, lightColor)
+		snap = snapshotText80(vs, isSecondPage, isAltText, lightColor)
 		applyNTSCFilter = false
 	case VideoText40RGB:
-		snap = snapshotText40RGB(vs, isSecondPage)
+		snap = snapshotText40RGB(vs, isSecondPage, isAltText)
 		applyNTSCFilter = false
 	case VideoGR:
 		snap = snapshotLoRes(vs, isSecondPage, lightColor)
@@ -90,11 +91,11 @@ func snapshotByMode(vs VideoSource, videoMode uint16, screenMode int) *image.RGB
 		applyNTSCFilter := screenMode != ScreenModeGreen
 		switch mixMode {
 		case VideoMixText40:
-			bottom = snapshotText40(vs, isSecondPage, lightColor)
+			bottom = snapshotText40(vs, isSecondPage, isAltText, lightColor)
 		case VideoMixText80:
-			bottom = snapshotText80(vs, isSecondPage, lightColor)
+			bottom = snapshotText80(vs, isSecondPage, isAltText, lightColor)
 		case VideoMixText40RGB:
-			bottom = snapshotText40RGB(vs, isSecondPage)
+			bottom = snapshotText40RGB(vs, isSecondPage, isAltText)
 			applyNTSCFilter = false
 		}
 		if applyNTSCFilter {

screen/snapshotsDebug.go

@@ -79,6 +79,10 @@ func VideoModeName(vs VideoSource) string {
 		name += "-PAGE2"
 	}
 
+	if (videoMode & VideoAltText) != 0 {
+		name += "-ALT"
+	}
+
 	switch mixMode {
 	case VideoMixText40:
 		name += "-MIX40"
@@ -130,7 +134,7 @@ func doubleWidthFilter(in *image.RGBA) *image.RGBA {
 }
 
 // SnapshotCharacterGenerator shows the current character set
-func SnapshotCharacterGenerator(vs VideoSource) *image.RGBA {
+func SnapshotCharacterGenerator(vs VideoSource, isAltText bool) *image.RGBA {
 	text := make([]uint8, textLines*text40Columns)
 	for l := 0; l < textLines; l++ {
 		for c := 0; c < text40Columns; c++ {
@@ -144,5 +148,5 @@ func SnapshotCharacterGenerator(vs VideoSource) *image.RGBA {
 		}
 	}
 
-	return renderText(vs, text, nil, color.White)
+	return renderText(vs, text, isAltText, nil, color.White)
 }

screen/testScenarios.go

@@ -114,7 +114,7 @@ func (ts *TestScenario) GetVideoMemory(secondPage bool, ext bool) []uint8 {
 }
 
 // GetCharacterPixel returns the pixel as output by the character generator
-func (ts *TestScenario) GetCharacterPixel(char uint8, rowInChar int, colInChar int) bool {
+func (ts *TestScenario) GetCharacterPixel(char uint8, rowInChar int, colInChar int, isAltText bool, isFlashedFrame bool) bool {
 	// We don't have a character generator. We will return a square or blank for spaces
 	if char&0x3f == 0x20 {
 		return false // Space char

screen/text.go

@@ -3,6 +3,7 @@ package screen
 import (
 	"image"
 	"image/color"
+	"time"
 )
 
 const (
@@ -12,25 +13,25 @@ const (
 	textLines     = 24
 )
 
-func snapshotText40(vs VideoSource, isSecondPage bool, light color.Color) *image.RGBA {
+func snapshotText40(vs VideoSource, isSecondPage bool, isAltText bool, light color.Color) *image.RGBA {
 	text := getTextFromMemory(vs, isSecondPage, false)
-	return renderText(vs, text, nil /*colorMap*/, light)
+	return renderText(vs, text, isAltText, nil /*colorMap*/, light)
 }
 
-func snapshotText80(vs VideoSource, isSecondPage bool, light color.Color) *image.RGBA {
+func snapshotText80(vs VideoSource, isSecondPage bool, isAltText bool, light color.Color) *image.RGBA {
 	text := getText80FromMemory(vs, isSecondPage)
-	return renderText(vs, text, nil /*colorMap*/, light)
+	return renderText(vs, text, isAltText, nil /*colorMap*/, light)
 }
 
-func snapshotText40RGB(vs VideoSource, isSecondPage bool) *image.RGBA {
+func snapshotText40RGB(vs VideoSource, isSecondPage bool, isAltText bool) *image.RGBA {
 	text := getTextFromMemory(vs, isSecondPage, false)
 	colorMap := getTextFromMemory(vs, isSecondPage, true)
-	return renderText(vs, text, colorMap, nil)
+	return renderText(vs, text, isAltText, colorMap, nil)
 }
 
 func snapshotText40RGBColors(vs VideoSource, isSecondPage bool) *image.RGBA {
 	colorMap := getTextFromMemory(vs, isSecondPage, true)
-	return renderText(vs, nil /*text*/, colorMap, nil)
+	return renderText(vs, nil /*text*/, false, colorMap, nil)
 }
 
 func getText80FromMemory(vs VideoSource, isSecondPage bool) []uint8 {
@@ -77,7 +78,10 @@ func getRGBTextColor(pixel bool, colorKey uint8) color.Color {
 
 }
 
-func renderText(vs VideoSource, text []uint8, colorMap []uint8, light color.Color) *image.RGBA {
+func renderText(vs VideoSource, text []uint8, isAltText bool, colorMap []uint8, light color.Color) *image.RGBA {
+	// Flash mode is 2Hz (host time)
+	isFlashedFrame := time.Now().Nanosecond() > (1 * 1000 * 1000 * 1000 / 2)
+
 	columns := len(text) / textLines
 	if text == nil {
 		columns = text40Columns
@@ -102,7 +106,7 @@ func renderText(vs VideoSource, text []uint8, colorMap []uint8, light color.Colo
 				char = 79 + 128 // Debug screen filed with O
 			}
 
-			pixel := vs.GetCharacterPixel(char, rowInChar, colInChar)
+			pixel := vs.GetCharacterPixel(char, rowInChar, colInChar, isAltText, isFlashedFrame)
 
 			var colour color.Color
 			if colorMap != nil {

screen/videoSource.go

@@ -28,6 +28,7 @@ const (
 const (
 	VideoModifiersMask uint16 = 0xf000
 	VideoSecondPage    uint16 = 0x1000
+	VideoAltText       uint16 = 0x2000
 )
 
 // VideoSource provides the info to build the video output
@@ -39,7 +40,7 @@ type VideoSource interface {
 	// GetVideoMemory returns a slice to the video memory pages
 	GetVideoMemory(secondPage bool, ext bool) []uint8
 	// GetCharactePixel returns the pixel as output by the character generator
-	GetCharacterPixel(char uint8, rowInChar int, colInChar int) bool
+	GetCharacterPixel(char uint8, rowInChar int, colInChar int, isAltText bool, isFlashedFrame bool) bool
 	// GetSuperVideoMemory returns a slice to the SHR video memory
 	GetSuperVideoMemory() []uint8
 }

videoSourceImpl.go

@@ -1,8 +1,6 @@
 package izapple2
 
 import (
-	"time"
-
 	"github.com/ivanizag/izapple2/screen"
 )
 
@@ -34,6 +32,8 @@ func (a *Apple2) GetCurrentVideoMode() uint16 {
 	isRGB160Mode := isDoubleResMode && rgbFlag1 && !rgbFlag2
 
 	isMixMode := a.io.isSoftSwitchActive(ioFlagMixed)
+	isSecondPage := a.io.isSoftSwitchActive(ioFlagSecondPage) && !a.mmu.store80Active
+	isAltText := a.isApple2e && a.io.isSoftSwitchActive(ioFlagAltChar)
 
 	var mode uint16
 	if isSuperHighResMode {
@@ -76,10 +76,12 @@ func (a *Apple2) GetCurrentVideoMode() uint16 {
 			mode |= screen.VideoMixText40
 		}
 	}
-	isSecondPage := a.io.isSoftSwitchActive(ioFlagSecondPage) && !a.mmu.store80Active
 	if isSecondPage {
 		mode |= screen.VideoSecondPage
 	}
+	if isAltText {
+		mode |= screen.VideoAltText
+	}
 
 	return mode
 }
@@ -111,11 +113,7 @@ func (a *Apple2) GetSuperVideoMemory() []uint8 {
 }
 
 // GetCharacterPixel returns the pixel as output by the character generator
-func (a *Apple2) GetCharacterPixel(char uint8, rowInChar int, colInChar int) bool {
+func (a *Apple2) GetCharacterPixel(char uint8, rowInChar int, colInChar int, isAltText bool, isFlashedFrame bool) bool {
-	// Flash mode is 2Hz (host time)
-	isFlashedFrame := time.Now().Nanosecond() > (1 * 1000 * 1000 * 1000 / 2)
-	isAltText := a.io.isSoftSwitchActive(ioFlagAltChar)
-
 	var pixel bool
 	if a.isApple2e {
 		vid6 := (char & 0x40) != 0