79 function is_opaque(layer) {  argument
80   if (layer.color == undefined || layer.color.a == undefined || layer.color.a != 1) return false;
81   return layer.isOpaque;
84 function fills_color(layer) {  argument
85   return layer.color && layer.color.a > 0 &&
86       layer.color.r >= 0 && layer.color.g >= 0 &&
87       layer.color.b >= 0;
90 function draws_shadows(layer) {  argument
91   return layer.shadowRadius && layer.shadowRadius > 0;
94 function has_blur(layer) {  argument
95   return layer.backgroundBlurRadius && layer.backgroundBlurRadius > 0;
98 function has_effects(layer) {  argument
100   if (layer.type === 'ColorLayer') return true;
103   return layer.type === 'EffectLayer' &&
104       (fills_color(layer) || draws_shadows(layer) || has_blur(layer))
107 function is_hidden_by_policy(layer) {  argument
108   return layer.flags & FLAG_HIDDEN == FLAG_HIDDEN || 
110     layer.id == 0x7FFFFFFD;
117 function is_visible(layer, hiddenByPolicy, includesCompositionState) {  argument
120     return !is_empty(layer.visibleRegion);
127   if (!layer.activeBuffer && !has_effects(layer)) {
131   if (!layer.color || !layer.color.a || layer.color.a == 0) {
135   if (layer.occludedBy && layer.occludedBy.length > 0) {
139   if (!layer.bounds || is_empty_rect(layer.bounds)) {
146 function get_visibility_reason(layer) {  argument
147   if (layer.type === 'ContainerLayer') {
151   if (is_hidden_by_policy(layer)) {
155   if (layer.hidden) {
159   let isBufferLayer = (layer.type === 'BufferStateLayer' || layer.type === 'BufferQueueLayer');
160   if (isBufferLayer && (!layer.activeBuffer ||
161     layer.activeBuffer.height === 0 || layer.activeBuffer.width === 0)) {
165   if (!layer.color || !layer.color.a || layer.color.a == 0) {
169   if (is_rect_empty_and_valid(layer.crop)) {
173   if (!layer.bounds || is_empty_rect(layer.bounds)) {  
177   if (is_transform_invalid(layer.transform)) {
180   if (layer.isRelativeOf && layer.zOrderRelativeOf == -1) {
184   let isEffectLayer = (layer.type === 'EffectLayer');
185   if (isEffectLayer && !fills_color(layer) && !draws_shadows(layer) && !has_blur(layer)) {
189   if (layer.occludedBy && layer.occludedBy.length > 0) {
190     return 'Layer is occluded by:' + layer.occludedBy.join();
193   if (layer.visible) {
215 function screen_bounds(layer) {  argument
216   if (layer.screenBounds) return layer.screenBounds;
217   let transformMatrix = layer.transform;
218   var tx = layer.position ? layer.position.x || 0 : 0;
219   var ty = layer.position ? layer.position.y || 0 : 0;
223   return multiply_rect(transformMatrix, layer.bounds);
228   const layers = rootLayers.filter(layer => !layer.isRelativeOf);
229 …yerMap, layers, {opaqueRects:[], transparentRects:[], screenBounds:null}, (layer, globalState) => {
231     if (layer.name.startsWith("Root#0") && layer.sourceBounds) {
232 …globalState.screenBounds = {left:0,  top:0, bottom:layer.sourceBounds.bottom, right:layer.sourceBo…
235     const visible = is_visible(layer, layer.hidden, includesCompositionState);
237       let fullyOccludes = (testLayer) => contains(testLayer, layer);
238 …   let partiallyOccludes = (testLayer) => overlaps(screen_bounds(testLayer), screen_bounds(layer));
239       let covers = (testLayer) => overlaps(screen_bounds(testLayer), screen_bounds(layer));
241       layer.occludedBy = globalState.opaqueRects.filter(fullyOccludes).map(layer => layer.id);
242 …layer.partiallyOccludedBy = globalState.opaqueRects.filter(partiallyOccludes).map(layer => layer.i…
243       layer.coveredBy = globalState.transparentRects.filter(covers).map(layer => layer.id);
245       if (is_opaque(layer)) {
246         globalState.opaqueRects.push(layer);
248           globalState.transparentRects.push(layer);
252     layer.visible = is_visible(layer, layer.hidden, includesCompositionState);
253     if (!layer.visible) {
254       layer.invisibleDueTo = get_visibility_reason(layer);
265     const traverseList = relatives.concat(children.filter(layer => !layer.isRelativeOf));
268     traverseList.filter((layer) => layer.z >=0).forEach(layer => {
269       traverse_top_to_bottom(layerMap, [layer], globalState, fn);
274     traverseList.filter((layer) => layer.z < 0).forEach(layer => {
275       traverse_top_to_bottom(layerMap, [layer], globalState, fn);
283   traverse(layerMap, rootLayers, (layer, parent) => {
285     layer.hidden = is_hidden_by_policy(layer) || parentHidden;
286     layer.verboseFlags = flags_to_string(layer.flags);
288     if (!layer.bounds) {
289       if (!layer.sourceBounds) {
290         layer.bounds = layer.sourceBounds;
292         layer.bounds = parent.bounds;
294         layer.bounds = {left:0, top:0, right:0, bottom:0};