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package svg
import (
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"b612.me/astro/internal/timenote"
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"fmt"
"html"
"math"
"strings"
"time"
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"b612.me/astro"
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"b612.me/astro/basic"
eclipsecore "b612.me/astro/eclipse"
"b612.me/astro/internal/svgasset"
"b612.me/astro/internal/svgchart"
"b612.me/astro/internal/svgmap"
)
// LunarEclipseDetailedSVGOptions 控制 详细版式的月食组合图：摘要、穿影示意图与世界可见性底图合成一页。
// LunarEclipseDetailedSVGOptions controls the detailed combined lunar-eclipse chart: summary, shadow-path
// diagram, and world visibility map on a single page.
type LunarEclipseDetailedSVGOptions struct {
// Width 与 Height 是 SVG 画布尺寸；<=0 时使用 1000x1414 的 NASA 开本。版式按 Height 推导：
// 高度不足时先压缩穿影示意图，再压缩底图；两者都低于下限（示意图 200、底图 180）、
// 数据块行距或底图图例行放不下时返回 false。
// Width and Height are the SVG canvas size; values <= 0 use the 1000x1414 NASA page. The page
// stack is derived from Height: a short canvas shrinks the shadow-path diagram first and the
// map second, and the renderer returns false when the diagram and map minima (200 and 180), the
// data-block row spacing, or the map legend rows cannot be kept apart.
Width int
Height int
// Language 为 "en" 时使用英文，其他值使用中文。
// Language uses English for "en" and Chinese otherwise.
Language string
// Location 控制显示时刻的时区；nil 使用 UTC+8。
// Location controls the display timezone; nil uses UTC+8.
Location * time . Location
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// TimeScale 选择图中时刻的时标：零值 UTC；
// nil 或 UTC（否则返回 false）。nil Location 在 UTC 下默认 UTC+8，
// TimeScale selects the label scale: the zero value is UTC; TimeScaleUT1 uses UT1 labels and requires
// Location to be nil or UTC (otherwise the renderer returns false).
TimeScale astro . TimeScale
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// Step 是月心路径采样步长；<=0 时使用 5 分钟。
// Step is the Moon-center path sampling step; values <= 0 use five minutes.
Step time . Duration
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// DisablePenumbralPhase 关闭底图可见性分区里的半影阶段，含义与 LunarEclipseMapSVGOptions 的同名字段一致；
// 零值即画半影。
// DisablePenumbralPhase turns the penumbral phase off in the base map partition, with the same
// meaning as the LunarEclipseMapSVGOptions field of that name; the zero value draws it.
DisablePenumbralPhase bool
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// Title 与 FooterNote 为空时自动生成。
// Empty Title and FooterNote use automatic text.
Title string
FooterNote string
}
// LunarEclipseDetailedSVG 生成 详细版式的月食组合图，默认模型与 LunarEclipseOnDate 一致：Danjon 为主，极浅半影回退 Chauvenet。
// LunarEclipseDetailedSVG renders a detailed combined lunar-eclipse chart with the default model of
// LunarEclipseOnDate: Danjon, falling back to Chauvenet for ultra-shallow penumbral cases.
func LunarEclipseDetailedSVG ( date time . Time , options LunarEclipseDetailedSVGOptions ) ( string , bool ) {
model , ok := lunarEclipseDefaultShadowModel ( date )
if ! ok {
return "" , false
}
if model == eclipsecore . LunarEclipseShadowModelChauvenet {
return LunarEclipseDetailedSVGChauvenet ( date , options )
}
return LunarEclipseDetailedSVGDanjon ( date , options )
}
// LunarEclipseDetailedSVGDanjon 生成 详细版式月食组合图，使用 Danjon 影半径模型。
// LunarEclipseDetailedSVGDanjon renders a detailed chart with the Danjon shadow model.
func LunarEclipseDetailedSVGDanjon ( date time . Time , options LunarEclipseDetailedSVGOptions ) ( string , bool ) {
return lunarEclipseDetailedSVG ( date , options ,
basic . LunarEclipseDiagramDanjon , basic . LunarEclipseShadowGeometryAt , eclipsecore . ClosestLunarEclipseDanjon ,
eclipsecore . LunarEclipseShadowModelDanjon )
}
// LunarEclipseDetailedSVGChauvenet 生成 详细版式月食组合图，使用 Chauvenet 影半径模型。
// LunarEclipseDetailedSVGChauvenet renders a detailed chart with the Chauvenet shadow model.
func LunarEclipseDetailedSVGChauvenet ( date time . Time , options LunarEclipseDetailedSVGOptions ) ( string , bool ) {
return lunarEclipseDetailedSVG ( date , options ,
basic . LunarEclipseDiagramChauvenet , basic . LunarEclipseShadowGeometryChauvenetAt , eclipsecore . ClosestLunarEclipseChauvenet ,
eclipsecore . LunarEclipseShadowModelChauvenet )
}
func normalizeLunarEclipseDetailedSVGOptions ( options LunarEclipseDetailedSVGOptions ) LunarEclipseDetailedSVGOptions {
if options . Width <= 0 {
options . Width = 1000
}
if options . Height <= 0 {
options . Height = 1414
}
if options . Location == nil {
options . Location = time . FixedZone ( "UTC+8" , lunarEclipseSVGDefaultZone )
}
if strings . EqualFold ( options . Language , lunarEclipseSVGLanguageEnglish ) {
options . Language = lunarEclipseSVGLanguageEnglish
} else {
options . Language = lunarEclipseSVGLanguageChinese
}
return options
}
func lunarEclipseDetailedSVG (
date time . Time ,
options LunarEclipseDetailedSVGOptions ,
calculator lunarEclipseSVGCalculator ,
geometry func ( float64 ) basic . LunarEclipseShadowGeometry ,
finder lunarEclipseSVGFinder ,
model eclipsecore . LunarEclipseShadowModel ,
) ( string , bool ) {
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if options . TimeScale == astro . TimeScaleUT1 {
if options . Location != nil && options . Location != time . UTC {
return "" , false
}
options . Location = time . UTC
}
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options = normalizeLunarEclipseDetailedSVGOptions ( options )
diagram := calculator ( timeToTTJDE ( date ), basic . LunarEclipseDiagramOptions {
StepDays : durationToDays ( options . Step ),
})
if diagram . Eclipse . Type == basic . LunarEclipseNone || len ( diagram . Points ) == 0 {
return "" , false
}
info := lunarEclipseInfoFromBasic ( diagram . Eclipse , options . Location )
if finder != nil {
coreInfo := finder ( info . Maximum )
info . HasSaros = coreInfo . HasSaros
info . Saros = coreInfo . Saros
}
if ! validLunarEclipseDetailedSize ( options . Width , options . Height , info , options ) {
return "" , false
}
return renderLunarEclipseDetailedSVG (
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lunarEclipseDisplayInfo ( info , options . TimeScale ), info ,
diagram , geometry ( diagram . Eclipse . Maximum ), diagram . Eclipse . Maximum , options , model ,
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), true
}
// lunarEclipseDetailedView 汇总 详细版式各区块的位置。
type lunarEclipseDetailedView struct {
width , height float64
margin float64
metaY float64
blockY float64
diagramTop float64
diagramBottom float64
rowY float64
rowHeight float64
mapFrame svgmap . Frame
legendY float64
legendRows int
footerY float64
columnWidth , columnGap float64
}
// 详细版式的竖向固定量：标题/摘要/地心块占用顶部，示意图与底图分掉剩余高度。
const (
lunarEclipseDetailedDiagramTop = 268.0
lunarEclipseDetailedDiagramHeight = 368.0
lunarEclipseDetailedPanelHeight = 152.0
lunarEclipseDetailedPanelGap = 28.0
lunarEclipseDetailedMapGap = 26.0
lunarEclipseDetailedLegendGap = 30.0
lunarEclipseDetailedFooterReserve = 52.0
lunarEclipseDetailedMinDiagram = 200.0
lunarEclipseDetailedMinMapHeight = 180.0
lunarEclipseDetailedMinColumnWidth = 150.0
// 图例与页脚的字号、页脚基线到画布底边的固定内缩，以及两者之间的最小间隙。
lunarEclipseDetailedLegendFontSize = 10.0
lunarEclipseDetailedFooterFontSize = 11.0
lunarEclipseDetailedFooterInset = 42.0
lunarEclipseDetailedLegendFooterGap = 4.0
// 底图可见性图例：字号、图标加文本占位宽、列间隙、行距与页边内缩。
lunarEclipseDetailedMapLegendFontSize = 10.0
lunarEclipseDetailedMapLegendIconWidth = 24.0
lunarEclipseDetailedMapLegendGap = 12.0
lunarEclipseDetailedMapLegendLineStep = 22.0
lunarEclipseDetailedPageInset = 20.0
)
// lunarEclipseDetailedVerticalBudget 是扣掉顶部固定带、数据面板、图例与页脚后可分给示意图与底图的高度。
func lunarEclipseDetailedVerticalBudget ( height float64 ) float64 {
return height - ( lunarEclipseDetailedDiagramTop + lunarEclipseDetailedPanelGap +
lunarEclipseDetailedPanelHeight + lunarEclipseDetailedMapGap +
lunarEclipseDetailedLegendGap + lunarEclipseDetailedFooterReserve )
}
// lunarEclipseDetailedMapHeight 给出该画布下底图高度：先保示意图下限，再把剩余高度给底图，
// 底图宽度还要受画布宽度与 2:1 长宽比限制。
func lunarEclipseDetailedMapHeight ( width , height , margin float64 ) float64 {
budget := lunarEclipseDetailedVerticalBudget ( height )
return math . Min (( width - 2 * margin ) / 2 , budget - lunarEclipseDetailedMinDiagram )
}
// validLunarEclipseDetailedSize 报告详细版式在该画布尺寸下能否容下全部内容：
// 除竖向预算与栏宽外，数据块行距、图例带与页脚也必须互不压叠。
func validLunarEclipseDetailedSize ( width , height int , info LunarEclipseInfo , options LunarEclipseDetailedSVGOptions ) bool {
w , h := float64 ( width ), float64 ( height )
margin := math . Max ( 30 , math . Min ( 52 , w * 0.044 ))
budget := lunarEclipseDetailedVerticalBudget ( h )
mapHeight := lunarEclipseDetailedMapHeight ( w , h , margin )
if mapHeight < lunarEclipseDetailedMinMapHeight || budget - mapHeight < lunarEclipseDetailedMinDiagram {
return false
}
columnGap := math . Max ( 16 , w * 0.02 )
if ( w - 2 * margin - 2 * columnGap ) / 3 < lunarEclipseDetailedMinColumnWidth {
return false
}
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view := lunarEclipseDetailedViewFor ( info , options )
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if solarEclipsePanelsOverlap ( lunarEclipseDetailedPanelCells ( view , info , options )) {
return false
}
_ , legendBelow := svgchart . EstimatedTextExtents ( lunarEclipseDetailedMapLegendFontSize )
_ , footerBelow := svgchart . EstimatedTextExtents ( lunarEclipseDetailedFooterFontSize )
if view . footerY < view . legendY + legendBelow {
return false
}
// 页脚要留在白色页框内，越出画布就没有可读位置了。
return view . footerY + footerBelow <= h - 20
}
// lunarEclipseDetailedPanelContent 给出三栏数据块的内容：左栏历时、右栏接触时刻。
func lunarEclipseDetailedPanelContent (
info LunarEclipseInfo ,
options LunarEclipseDetailedSVGOptions ,
) ( string , [] svgchart . PanelRow , string , [] svgchart . PanelRow ) {
english := options . Language == lunarEclipseSVGLanguageEnglish
duration := func ( start , end time . Time ) string {
if start . IsZero () || end . IsZero () || ! end . After ( start ) {
return "-"
}
return formatSolarEclipseMapDuration ( end . Sub ( start ))
}
durationsTitle := "月食历时"
contactsTitle := "接触时刻"
if english {
durationsTitle = "Eclipse durations"
contactsTitle = "Eclipse contacts"
}
durations := [] svgchart . PanelRow {
{ Label : "半影食" , Value : duration ( info . PenumbralStart , info . PenumbralEnd )},
{ Label : "偏食" , Value : duration ( info . PartialStart , info . PartialEnd )},
{ Label : "全食" , Value : duration ( info . TotalStart , info . TotalEnd )},
}
if english {
durations [ 0 ]. Label , durations [ 1 ]. Label , durations [ 2 ]. Label = "Penumbral" , "Partial" , "Total"
}
contacts := [] svgchart . PanelRow {
{ Label : "P1 半影食始" , Value : info . PenumbralStart . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U1 初亏" , Value : info . PartialStart . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U2 食既" , Value : info . TotalStart . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "食甚" , Value : info . Maximum . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U3 生光" , Value : info . TotalEnd . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U4 复圆" , Value : info . PartialEnd . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "P4 半影食终" , Value : info . PenumbralEnd . In ( options . Location ). Format ( "15:04:05" )},
}
if english {
contacts = [] svgchart . PanelRow {
{ Label : "P1 penumbral begins" , Value : info . PenumbralStart . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U1 partial begins" , Value : info . PartialStart . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U2 total begins" , Value : info . TotalStart . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "Greatest" , Value : info . Maximum . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U3 total ends" , Value : info . TotalEnd . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "U4 partial ends" , Value : info . PartialEnd . In ( options . Location ). Format ( "15:04:05" )},
{ Label : "P4 penumbral ends" , Value : info . PenumbralEnd . In ( options . Location ). Format ( "15:04:05" )},
}
}
if ! info . HasTotal {
contacts [ 2 ]. Value , contacts [ 4 ]. Value = "-" , "-"
}
if ! info . HasPartial {
contacts [ 1 ]. Value , contacts [ 5 ]. Value = "-" , "-"
}
return durationsTitle , durations , contactsTitle , contacts
}
// lunarEclipseDetailedPanelCells 给出三栏数据块的矩形与内容：占位与绘制共用同一份几何。
func lunarEclipseDetailedPanelCells (
view lunarEclipseDetailedView ,
info LunarEclipseInfo ,
options LunarEclipseDetailedSVGOptions ,
) [] solarEclipsePanelCell {
durationsTitle , durations , contactsTitle , contacts := lunarEclipseDetailedPanelContent ( info , options )
right := view . margin + 2 * ( view . columnWidth + view . columnGap )
return [] solarEclipsePanelCell {
{ title : durationsTitle , rows : durations , box : svgchart . LabelBox {
X : view . margin , Y : view . rowY , Width : view . columnWidth , Height : view . rowHeight ,
}},
{ title : contactsTitle , rows : contacts , box : svgchart . LabelBox {
X : right , Y : view . rowY , Width : view . columnWidth , Height : view . rowHeight ,
}},
}
}
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func lunarEclipseDetailedViewFor ( info LunarEclipseInfo , options LunarEclipseDetailedSVGOptions ) lunarEclipseDetailedView {
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width , height := float64 ( options . Width ), float64 ( options . Height )
margin := math . Max ( 30 , math . Min ( 52 , width * 0.044 ))
view := lunarEclipseDetailedView {
width : width , height : height , margin : margin ,
metaY : 88 , blockY : 196 ,
diagramTop : lunarEclipseDetailedDiagramTop ,
rowHeight : lunarEclipseDetailedPanelHeight ,
}
view . columnGap = math . Max ( 16 , width * 0.02 )
view . columnWidth = ( width - 2 * margin - 2 * view . columnGap ) / 3
// 竖向是一条带栈：示意图与底图分掉固定带之外的高度；高度不足时两者一起缩，
// 到下限的画布由 validLunarEclipseDetailedSize 提前拒绝，这里不再兜底。
budget := lunarEclipseDetailedVerticalBudget ( height )
mapHeight := lunarEclipseDetailedMapHeight ( width , height , margin )
diagramHeight := math . Min ( lunarEclipseDetailedDiagramHeight , budget - mapHeight )
view . diagramBottom = view . diagramTop + diagramHeight
view . rowY = view . diagramBottom + lunarEclipseDetailedPanelGap
mapTop := view . rowY + view . rowHeight + lunarEclipseDetailedMapGap
mapWidth := mapHeight * 2
if limit := width - 2 * margin ; mapWidth > limit {
mapWidth = limit
mapHeight = mapWidth / 2
}
view . mapFrame = svgmap . Frame {
X : ( width - mapWidth ) / 2 , Y : mapTop , Width : mapWidth , Height : mapHeight ,
Projection : svgmap . ProjectionEquirectangular ,
}
view . legendY = mapTop + mapHeight + lunarEclipseDetailedLegendGap
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view . legendRows = len ( lunarEclipseMapLegendRows ( view . mapFrame , width , options . Language ,
lunarEclipseMapDrawsPenumbralBands ( info , ! options . DisablePenumbralPhase )))
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if view . legendRows < 1 {
view . legendRows = 1
}
// 页脚按图例实测高度往下排：图例带再往下压也不能与页脚同高。
_ , legendBelow := svgchart . EstimatedTextExtents ( lunarEclipseDetailedMapLegendFontSize )
footerAbove , _ := svgchart . EstimatedTextExtents ( lunarEclipseDetailedFooterFontSize )
footerFloor := view . legendY + float64 ( view . legendRows - 1 ) * lunarEclipseDetailedMapLegendLineStep +
legendBelow + lunarEclipseDetailedLegendFooterGap + footerAbove
view . footerY = math . Max ( height - lunarEclipseDetailedFooterInset , footerFloor )
return view
}
func renderLunarEclipseDetailedSVG (
info LunarEclipseInfo ,
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geometry LunarEclipseInfo ,
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diagram basic . LunarEclipseDiagramResult ,
shadow basic . LunarEclipseShadowGeometry ,
tt float64 ,
options LunarEclipseDetailedSVGOptions ,
model eclipsecore . LunarEclipseShadowModel ,
) string {
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view := lunarEclipseDetailedViewFor ( info , options )
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english := options . Language == lunarEclipseSVGLanguageEnglish
title := options . Title
if title == "" {
date := info . Maximum . In ( options . Location ). Format ( "2006-01-02" )
if english {
title = fmt . Sprintf ( "Total Lunar Eclipse of %s" , date )
} else {
title = fmt . Sprintf ( "%s %s" , date , lunarEclipseSVGTypeName ( info . Type , "zh" ))
}
}
extent := diagram . PenumbraRadius + diagram . MoonRadius + 0.72
scale := math . Min (
( view . width - 2 * view . margin ) / ( 2 * extent ),
( view . diagramBottom - view . diagramTop ) / ( 2 * extent ),
)
if scale <= 0 || math . IsNaN ( scale ) || math . IsInf ( scale , 0 ) {
scale = 1
}
layout := lunarEclipseSVGLayout {
width : view . width , height : view . height ,
cx : view . width / 2 ,
cy : ( view . diagramTop + view . diagramBottom ) / 2 ,
scale : scale ,
diagramTop : view . diagramTop , diagramEnd : view . diagramBottom ,
diagramLeft : view . margin , diagramRight : view . width - view . margin ,
}
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penumbralBands := lunarEclipseMapDrawsPenumbralBands ( info , ! options . DisablePenumbralPhase )
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// 不动的元素先占位：数据块、底图、图例与页脚；示意图标注只在示意图带内选位置。
labels := & svgchart . LabelTable {}
for _ , cell := range lunarEclipseDetailedPanelCells ( view , info , options ) {
labels . Reserve ( cell . box . X , cell . box . Y , cell . box . Width , cell . box . Height )
}
labels . Reserve ( view . mapFrame . X , view . mapFrame . Y , view . mapFrame . Width , view . mapFrame . Height )
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for _ , row := range lunarEclipseMapLegendRows ( view . mapFrame , view . width , options . Language , penumbralBands ) {
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for _ , item := range row {
labels . ReserveText ( item . x , item . y , lunarEclipseDetailedMapLegendFontSize , item . text , "start" )
}
}
labels . ReserveText ( view . margin , view . footerY , lunarEclipseDetailedFooterFontSize ,
lunarEclipseDetailedFooterText ( options , model ), "start" )
var b strings . Builder
fmt . Fprintf ( & b , `<svg xmlns="http://www.w3.org/2000/svg" width="%d" height="%d" viewBox="0 0 %d %d" role="img" aria-label="%s">` ,
options . Width , options . Height , options . Width , options . Height , html . EscapeString ( title ))
b . WriteString ( `<defs>` )
b . WriteString ( svgasset . MoonFaceSymbol ())
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writeLunarEclipseMapDefinitions ( & b , view . mapFrame , geometry , penumbralBands )
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b . WriteString ( `</defs>` )
b . WriteString ( `<rect width="100%" height="100%" fill="#efefed"/>` )
fmt . Fprintf ( & b , `<rect x="22" y="18" width="%.3f" height="%.3f" fill="#ffffff" stroke="#c9c9c6" stroke-width="1.2"/>` ,
view . width - 44 , view . height - 36 )
titleText := title
if options . Title != "" {
titleText = svgchart . EllipsizeText ( title , view . width - 52 , 25 )
}
fmt . Fprintf ( & b , `<text x="%.3f" y="52" fill="#111111" font-family="Georgia, 'Times New Roman', serif" font-size="25" font-weight="700" text-anchor="middle">%s</text>` ,
view . width / 2 , html . EscapeString ( titleText ))
writeLunarEclipseDetailedSummary ( & b , labels , info , shadow , view , options )
writeLunarEclipseDetailedGeocentricBlocks ( & b , labels , tt , view , options )
writeLunarEclipseDiagram ( & b , layout , diagram , options . Language , labels )
writeLunarEclipseDetailedPanels ( & b , info , shadow , scale , view , options )
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writeLunarEclipseMapRegions ( & b , view . mapFrame , geometry , penumbralBands )
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view . mapFrame . WriteFrame ( & b )
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writeLunarEclipseMapLegend ( & b , view . mapFrame , view . width , options . Language , penumbralBands )
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writeLunarEclipseDetailedFooter ( & b , view , options , model )
b . WriteString ( `</svg>` )
return b . String ()
}
// writeLunarEclipseDetailedSummary 写标题下居中的四行摘要。
func writeLunarEclipseDetailedSummary (
b * strings . Builder ,
labels * svgchart . LabelTable ,
info LunarEclipseInfo ,
shadow basic . LunarEclipseShadowGeometry ,
view lunarEclipseDetailedView ,
options LunarEclipseDetailedSVGOptions ,
) {
english := options . Language == lunarEclipseSVGLanguageEnglish
zone , _ := info . Maximum . In ( options . Location ). Zone ()
lines := make ([] string , 0 , 4 )
if english {
lines = append ( lines , fmt . Sprintf ( "Greatest Eclipse = %s (%s) | Umbral magnitude = %.4f" ,
info . Maximum . In ( options . Location ). Format ( "15:04:05" ), zone , info . UmbralMagnitude ))
lines = append ( lines , fmt . Sprintf ( "Penumbral magnitude = %.4f | Gamma = %.4f" ,
info . PenumbralMagnitude , shadow . Gamma ))
lines = append ( lines , fmt . Sprintf ( "P. Radius = %.4f° | U. Radius = %.4f° | Axis = %.4f°" ,
shadow . PenumbralRadiusDegrees , shadow . UmbralRadiusDegrees , shadow . AxisDegrees ))
lines = append ( lines , fmt . Sprintf ( "Saros series = %d | member %d of %d" , info . Saros . Series , info . Saros . Member , info . Saros . Count ))
} else {
lines = append ( lines , fmt . Sprintf ( "食甚 = %s（ ） ,
info . Maximum . In ( options . Location ). Format ( "15:04:05" ), zone , info . UmbralMagnitude ))
lines = append ( lines , fmt . Sprintf ( "半影食分 = %.4f | 伽马 = %.4f" , info . PenumbralMagnitude , shadow . Gamma ))
lines = append ( lines , fmt . Sprintf ( "半影半径 = %.4f° | 本影半径 = %.4f° | 影轴角距 = %.4f°" ,
shadow . PenumbralRadiusDegrees , shadow . UmbralRadiusDegrees , shadow . AxisDegrees ))
lines = append ( lines , fmt . Sprintf ( "沙罗序列 = %d | 第 %d / %d 个成员" , info . Saros . Series , info . Saros . Member , info . Saros . Count ))
}
if ! info . HasSaros {
lines [ len ( lines ) - 1 ] = ""
}
for index , line := range lines {
if line == "" {
continue
}
labels . ReserveText ( view . width / 2 , view . metaY + float64 ( index ) * 22 , 12.5 , line , "middle" )
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#293235" font-family="Arial, sans-serif" font-size="12.5" text-anchor="middle">%s</text>` ,
view . width / 2 , view . metaY + float64 ( index ) * 22 , html . EscapeString ( line ))
}
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zoneNote := timenote . Scale ( options . TimeScale , info . Maximum , options . Location , options . Language )
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labels . ReserveText ( view . width / 2 , view . metaY + 4 * 22 , 11 , zoneNote , "middle" )
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#7b8794" font-family="Arial, sans-serif" font-size="11" text-anchor="middle">%s</text>` ,
view . width / 2 , view . metaY + 4 * 22 , html . EscapeString ( zoneNote ))
}
func zoneOffsetSeconds ( value time . Time ) int {
_ , offset := value . Zone ()
return offset
}
func formatZoneOffset ( offsetSeconds int ) string {
sign := "+"
if offsetSeconds < 0 {
sign = "-"
offsetSeconds = - offsetSeconds
}
return fmt . Sprintf ( "%s%02d:%02d" , sign , offsetSeconds / 3600 , ( offsetSeconds % 3600 ) / 60 )
}
// writeLunarEclipseDetailedGeocentricBlocks 在球面两侧画日月地心坐标块。
func writeLunarEclipseDetailedGeocentricBlocks (
b * strings . Builder ,
labels * svgchart . LabelTable ,
tt float64 ,
view lunarEclipseDetailedView ,
options LunarEclipseDetailedSVGOptions ,
) {
english := options . Language == lunarEclipseSVGLanguageEnglish
titles := [ 2 ] string { "食甚时的太阳（地心坐标）" , "食甚时的月亮（地心坐标）" }
if english {
titles = [ 2 ] string { "Sun at greatest eclipse" , "Moon at greatest eclipse" }
}
sunRa , sunDec := basic . SunApparentRaDec ( tt )
moonRa , moonDec := basic . HMoonTrueRaDec ( tt )
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sunSd := basic . SolarEclipseSunSemidiameter ( tt , basic . SolarEclipseSunRadiusStandard )
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moonSd := basic . MoonSemidiameter ( tt )
blocks := [ 2 ][] svgchart . PanelRow {
{
{ Label : "赤经 R.A." , Value : formatSolarEclipseRA ( sunRa )},
{ Label : "赤纬 Dec." , Value : formatSolarEclipseDec ( sunDec )},
{ Label : "视半径 S.D." , Value : formatSolarEclipseArcsec ( sunSd )},
{ Label : "地平视差 H.P." , Value : formatSolarEclipseArcsec ( horizontalParallaxArcsecRatio ( sunSd , 6378.137 / 696000.0 ))},
},
{
{ Label : "赤经 R.A." , Value : formatSolarEclipseRA ( moonRa )},
{ Label : "赤纬 Dec." , Value : formatSolarEclipseDec ( moonDec )},
{ Label : "视半径 S.D." , Value : formatSolarEclipseArcsec ( moonSd )},
{ Label : "地平视差 H.P." , Value : formatSolarEclipseArcsec ( horizontalParallaxArcsecRatio ( moonSd , 6378.137 / 1737.4 ))},
},
}
if english {
for index := range blocks {
blocks [ index ][ 3 ]. Label = "H.P."
}
}
blockWidth := math . Min ( 212 , ( view . width - 2 * view . margin - 40 ) / 2 )
for index := 0 ; index < 2 ; index ++ {
x := view . margin
if index == 1 {
x = view . width - view . margin - blockWidth
}
fmt . Fprintf ( b , `<g class="lunar-geocentric-block">` )
labels . ReserveText ( x , view . blockY + 11 , 12 , titles [ index ], "start" )
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#111827" font-family="Georgia, 'Times New Roman', serif" font-size="12" font-weight="700">%s</text>` ,
x , view . blockY + 11 , html . EscapeString ( titles [ index ]))
for rowIndex , row := range blocks [ index ] {
rowY := view . blockY + 30 + float64 ( rowIndex ) * 17
labels . ReserveText ( x , rowY , 10.5 , row . Label , "start" )
labels . ReserveText ( x + blockWidth , rowY , 10.5 , row . Value , "end" )
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#475569" font-family="Arial, sans-serif" font-size="10.5">%s</text>` ,
x , rowY , html . EscapeString ( row . Label ))
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#0f172a" font-family="Arial, sans-serif" font-size="10.5" font-weight="700" text-anchor="end">%s</text>` ,
x + blockWidth , rowY , html . EscapeString ( row . Value ))
}
b . WriteString ( `</g>` )
}
}
// horizontalParallaxArcsecRatio 由视半径换算地平视差：sin(HP) = sin(SD) ×
func horizontalParallaxArcsecRatio ( semidiameterArcsec , radiusRatio float64 ) float64 {
sine := math . Sin ( semidiameterArcsec / 3600 * math . Pi / 180 )
return math . Asin ( math . Max ( - 1 , math . Min ( 1 , sine * radiusRatio ))) * 180 / math . Pi * 3600
}
// writeLunarEclipseDetailedPanels 写三栏：历时、弧分比例尺、接触时刻。
func writeLunarEclipseDetailedPanels (
b * strings . Builder ,
info LunarEclipseInfo ,
shadow basic . LunarEclipseShadowGeometry ,
diagramScale float64 ,
view lunarEclipseDetailedView ,
options LunarEclipseDetailedSVGOptions ,
) {
for _ , cell := range lunarEclipseDetailedPanelCells ( view , info , options ) {
writeLunarEclipseDetailedPanel ( b , cell . box . X , cell . box . Y , cell . box . Width , cell . box . Height , cell . title , cell . rows )
}
writeLunarEclipseArcMinuteScaleBar ( b , view , shadow , diagramScale )
}
func writeLunarEclipseDetailedPanel (
b * strings . Builder ,
x , y , width , height float64 ,
title string ,
rows [] svgchart . PanelRow ,
) {
svgchart . WritePanelBox ( b , "lunar-detailed-panel" , x , y , width , height , title , rows )
}
// writeLunarEclipseArcMinuteScaleBar 画穿影示意图的弧分比例尺。
// 示意图以"月球半径"为单位，一个月球半径对应真实角径 asin(1/月距)，据此换算弧分。
func writeLunarEclipseArcMinuteScaleBar (
b * strings . Builder ,
view lunarEclipseDetailedView ,
shadow basic . LunarEclipseShadowGeometry ,
diagramScale float64 ,
) {
if shadow . MoonDistanceEarthRadii <= 0 || diagramScale <= 0 {
return
}
// 示意图以"月球半径"为单位，一个月球半径对应的真实角径是 asin(R月 / 月距)，不是地球视差。
moonSemidiameterArcmin := math . Asin (( lunarMoonRadiusKM / lunarEarthRadiusKM ) / shadow . MoonDistanceEarthRadii ) * 180 / math . Pi * 60
if moonSemidiameterArcmin <= 0 {
return
}
pixelsPerArcmin := diagramScale / moonSemidiameterArcmin
target := 150.0
step := math . Pow ( 10 , math . Floor ( math . Log10 ( target / pixelsPerArcmin )))
for _ , multiplier := range [] float64 { 1 , 2 , 5 , 10 } {
if step * multiplier >= target / pixelsPerArcmin {
step *= multiplier
break
}
}
barWidth := step * pixelsPerArcmin
centreX := view . margin + view . columnWidth + view . columnGap + view . columnWidth / 2
y := view . rowY + view . rowHeight / 2
fmt . Fprintf ( b , `<g class="lunar-scale-bar"><line x1="%.3f" y1="%.3f" x2="%.3f" y2="%.3f" stroke="#334155" stroke-width="1"/>` ,
centreX - barWidth / 2 , y , centreX + barWidth / 2 , y )
for _ , tick := range [] float64 { 0 , 0.25 , 0.5 , 0.75 , 1 } {
x := centreX - barWidth / 2 + tick * barWidth
length := 5.0
if tick == 0 || tick == 1 {
length = 9
}
fmt . Fprintf ( b , `<line x1="%.3f" y1="%.3f" x2="%.3f" y2="%.3f" stroke="#334155" stroke-width="1"/>` ,
x , y - length / 2 , x , y + length / 2 )
}
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#334155" font-family="Arial, sans-serif" font-size="10" text-anchor="middle">0</text>` ,
centreX - barWidth / 2 , y - 10 )
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#334155" font-family="Arial, sans-serif" font-size="10" text-anchor="middle">%.0f</text>` ,
centreX + barWidth / 2 , y - 10 , step )
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#7b8794" font-family="Arial, sans-serif" font-size="10" text-anchor="middle">角分</text>` ,
centreX , y + 22 )
b . WriteString ( `</g>` )
}
// lunarEclipseDetailedFooterText 是页脚说明：默认模型会在极浅半影上回退 Chauvenet，必须写出实际用的那套。
func lunarEclipseDetailedFooterText ( options LunarEclipseDetailedSVGOptions , model eclipsecore . LunarEclipseShadowModel ) string {
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return lunarEclipseDetailedFooterTextBase ( options , model )
}
func lunarEclipseDetailedFooterTextBase ( options LunarEclipseDetailedSVGOptions , model eclipsecore . LunarEclipseShadowModel ) string {
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if options . FooterNote != "" {
return options . FooterNote
}
if options . Language == lunarEclipseSVGLanguageEnglish {
return "Shadow-path diagram uses the " + lunarEclipseShadowModelName ( model ) + " shadow model; the lower map marks where the whole eclipse is visible, where the Moon rises or sets eclipsed, and where it is not visible. Natural Earth 1:50m physical land, no administrative boundaries."
}
return "穿影示意图使用 " + lunarEclipseShadowModelName ( model ) + " 影半径模型；下方底图区分全程可见、带食月出、带食月落与不可见四类区域。Natural Earth 1:50m 物理陆地底图，不含行政边界。"
}
func writeLunarEclipseDetailedFooter (
b * strings . Builder ,
view lunarEclipseDetailedView ,
options LunarEclipseDetailedSVGOptions ,
model eclipsecore . LunarEclipseShadowModel ,
) {
// 页脚按页宽折行、按画布底边截断，首行位置不变；默认说明放得下时折行结果仍是同一行。
maxWidth := view . width - 2 * view . margin
lines := svgchart . TruncateTextLines (
svgchart . WrapText ( lunarEclipseDetailedFooterText ( options , model ), maxWidth , lunarEclipseDetailedFooterFontSize ),
maxWidth , lunarEclipseDetailedFooterFontSize ,
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svgchart . BaselineLineLimit ( lunarEclipseDetailedFooterFontSize , svgchart . FooterLineHeight ( lunarEclipseDetailedFooterFontSize ),
view . footerY , view . height - svgchart . FooterBottomPadding ( lunarEclipseDetailedFooterFontSize )))
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for index , line := range lines {
fmt . Fprintf ( b , `<text x="%.3f" y="%.3f" fill="#596164" font-family="Georgia, 'Times New Roman', serif" font-size="%.0f">%s</text>` ,
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view . margin , view . footerY + float64 ( index ) * svgchart . FooterLineHeight ( lunarEclipseDetailedFooterFontSize ),
lunarEclipseDetailedFooterFontSize , html . EscapeString ( line ))
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}
}
const (
// lunarMoonRadiusKM 与 lunarEarthRadiusKM 只用于把示意图的"月球半径"刻度换算成角分比例尺。
lunarMoonRadiusKM = 1737.4
lunarEarthRadiusKM = 6378.137
)
